Surging!
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=17748
Printed Date: September-27-2024 at 5:31pm
Topic: Surging!
Posted By: WhiteLakeSkier
Subject: Surging!
Date Posted: May-26-2010 at 10:00pm
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Well everything was running fine. Now I have a few problems.
When you gas it, it hesitates. Also if you give it gas and bring it back to neutral you can tell it is close to stalling. anything to do with idle mixture screws? When under WOT it will go from 4400 to about 3100 and then surge. if you lower the throttle, it will lower the rpm and continue to surge. then if you bring it back to WOT it will go up a bit and do the surging. Anything to do with vent tube? my tanks tube does not run to the outside of the boat. It comes out an inch or so and ends. I have the timing set correctly at 10 degrees BTDC. Fresh 93 octane fuel. I always add bottle of fuel treatment and carb/injector cleaner stuff from the station at fill up. Fresh screw on fuel filter. the line for a majority of the length is copper. I have a harbor freight vacuum gauge on screwed into the manifold while I'm running it, problem? ------------- www.correctcraftfan.com/diaries/details.asp?ID=5120&sort=&pagenum=1 - 1961 CC Custom American Skier |
Replies:
Posted By: SNobsessed
Date Posted: May-27-2010 at 12:41am
Letting gas fumes vent into your bilge is a bad bad situation. Don't go boating again until this is fixed. You are lucky to be alive! Get that vent run to the outside of the hull. Drill a new hole & run the hose out if you have no other option. Can't help with the surging, although it does sound like a carb problem. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
WhiteLakeSkier wrote:Posted By: GottaSki
Date Posted: May-27-2010 at 12:57am
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Surging is a fuel delivery problem. Likely a restriction in the fuel pickup plumbing.
Don't let it persist, the lean condition can cause serious damage. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: WhiteLakeSkier
Date Posted: May-27-2010 at 1:30am
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Nothing to do with idle mixture screw right? I had to lean them out since I had quite a smokey exhaust. they are less than 5 turns out. Common sense tells me Idle mixture deals only with idle but hey I might be wrong. ------------- www.correctcraftfan.com/diaries/details.asp?ID=5120&sort=&pagenum=1 - 1961 CC Custom American Skier |
Posted By: 81nautique
Date Posted: May-27-2010 at 10:21am
Nothing to do with your idle mixture screws but if you have them 5 turns out your way off base. Screw them both closed (righty tighty)until they gently seat(don't tighten them) then unscrew (lefty loosy) 1.5 turns and leave them alone until you find your fuel delivery problem. I would have to ask Chris (79) or Tom (Gottaski)if either ever gets a chance to write a step by step carb tuning post so we can make a sticky of it. We see the same question weekly all over the forum so it would be very useful. ------------- You can’t change the wind but you can adjust your sails |
Posted By: WhiteLakeSkier
Date Posted: May-27-2010 at 12:38pm
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I did set them by going 1.5 turns out, then adjusting. I didn't remember exactly what they were at for reference, but I knew they were less than 5. But none if that relates to the surging I suppose.
So, the carb isn't getting enough fuel. Why doesent it just run that way all the time instead of surging? I mean it seems that if something was stuck in the tank pickup, it would be starved of fuel continuously until it went through to the filter, and would just run continuously bogged out? Where should I begin looking? Can it be said the problem is not the carburetor for sure and I have to look at what's before it? ------------- www.correctcraftfan.com/diaries/details.asp?ID=5120&sort=&pagenum=1 - 1961 CC Custom American Skier |
Posted By: 81nautique
Date Posted: May-27-2010 at 12:51pm
Look at any place there could be a restriction, ie: anti siphon valve, fuel filter/water separator, the brass screen on the carb inlet. You've done a lot of work on that boat recently and you may have jarred some crud lose that was sitting in your tank. Report back, we'll have you running before first snow fall. ------------- You can’t change the wind but you can adjust your sails |
Posted By: 79nautique
Date Posted: May-27-2010 at 1:00pm
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two problems,
first stumble, adjust the accell pump until you get a steady stream from the get go, this can be done without the engine on, also it might require a new accel pump in the carb, but asjust first if you can't get a full stream for the full stroke, then replace. the next issue is fuel delivery. Bad fuel pump, or anti-shipon valve, but just get a new pump and I bet that fixes the problem, Fix the vent correctly too, has nothing to do with it unless it's clogged. So fuel pump, test with gauge to verify bad 5.5 lbs min. Clean antishipon valve, make sure vent is clear and connect to the outside. If fuel pressure is good, valve is clean and vent is clear and you still have the problem, raise the float. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: GottaSki
Date Posted: May-27-2010 at 1:05pm
Your thinking too much. You have the answers, now its time to take it apart. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: WhiteLakeSkier
Date Posted: May-27-2010 at 1:50pm
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Alright sounds good. Now how do I check the accl pump and adjust? ------------- www.correctcraftfan.com/diaries/details.asp?ID=5120&sort=&pagenum=1 - 1961 CC Custom American Skier |
Posted By: 79nautique
Date Posted: May-27-2010 at 3:02pm
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disconnect the throttle cable at the carb, remove flame arrestor, move throtle arm on carb slowly as your looking down the primary barrels, look for a stream of gas in the center of each barrel in the front (primary). the stream should start almost as soon as the throttle is moved and continue for the full stroke. If it doesn't just in front of the throtle lever there is a nut below the accel pump diaphram adjust that until you get a steady stream for the entire stroke of the throtle. If you cannot get that then the pump is bad and needs replaced. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: horkn
Date Posted: May-27-2010 at 8:05pm
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I'm guessing its either the anti siphon valve being plugged, or the fuel pump.
Even if the accel pump was bad, it wouldn't go from 4k to 3k with no change in throttle. Now a bad fuel pump could do it too, but start with the cheap (actually free0 check of cleaning the anti siphon valve. Now the vent line, well that really is important. ------------- 78 martinique- refloored, reinforced, stringers re glassed, re engineered interior GT40P heads Edelbrock Performer intake acme 4 blade http://img.photobucket.com/albums/v64/horkn/fish/nautique.jpg |
Posted By: WhiteLakeSkier
Date Posted: May-27-2010 at 9:04pm
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Anti siphon valve, don't think my tank has one. Just the vent line and the fuel fill. Unless I don't know what an anti siphon valve is ------------- www.correctcraftfan.com/diaries/details.asp?ID=5120&sort=&pagenum=1 - 1961 CC Custom American Skier |
Posted By: horkn
Date Posted: May-28-2010 at 1:45am
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The anti siphon valve is right where the fuel line is attached to at the top of the fuel tank. it's brass,and threads into the fitting on the tank.
Many people, including myself have chased their tail by not checking this. Had I known there was one, and that they get clogged from time to time, I would have saved myself a lot of work,time, and money. Granted if I just fixed that, I would only have 240 hp and not 300+hp like I do now. ------------- 78 martinique- refloored, reinforced, stringers re glassed, re engineered interior GT40P heads Edelbrock Performer intake acme 4 blade http://img.photobucket.com/albums/v64/horkn/fish/nautique.jpg |
Posted By: 79nautique
Date Posted: May-28-2010 at 11:56am
I think you missed a few points.
This is why the accel pump has to be checked and what the fuel pump cannot cause. The other issue is a fuel delivery issue and the fuel pump and anti-shipon valve and vent come into play. 
keep guessing because the odds of it being the pump or anti-shipon are long compared to a low float, but the basics have to be checked first mechanics 101. The kicker is that it pretty much tops out and then has issues, thus a low float and no fuel in the primary bowl causing it. If the fuel pump or anti-shipon valve where the issue, it would never get to max RPM and crap out in the 3500 rpm range. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: WhiteLakeSkier
Date Posted: May-28-2010 at 12:40pm
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That just screws onto an elbow. I really don't think mine has any valve. When I did this boat, I left the original 12 gallon tank in there with these copper lines. I adjusted the accl. pump by tightening the nut. Is that the direction to adjust if you don't think your getting a constant stream? Yesterday while I was out fooling with it, It bogged down till stall and ended with a little backfire of sorts. Started back up afterwords however. Now to test the fuel pump, I have a harborfreight fuel pump/vacuum tester. Can I just screw directly into the top of the fuel pump and crank it over? I can't just splice in with it being a metal line.  ------------- www.correctcraftfan.com/diaries/details.asp?ID=5120&sort=&pagenum=1 - 1961 CC Custom American Skier |
Posted By: WhiteLakeSkier
Date Posted: May-28-2010 at 12:45pm
Check float level now? It will run strong up to WOT and then give it a few seconds and it starts getting screwy. lower the throttle a bit and still screwy. However last night I cruised around the lake at about 2000 or a little over plane and it ran fine. ------------- www.correctcraftfan.com/diaries/details.asp?ID=5120&sort=&pagenum=1 - 1961 CC Custom American Skier |
Posted By: 81nautique
Date Posted: May-28-2010 at 1:05pm
Sorry if I sound sarcastic but yes check the float level now, you're getting advice from a pretty good source so oblige and do what he says. Next time you're going to sit down and bake a cake here's a little reading for you to familiarize yourself with http://www.holley.com/data/TechService/Technical/Carburetor%20Tech%20Info.pdf - Holley carbs There are also tons of articles on holley carbs all over the web so take a few minutes and do a quick search, it will be worth your time. ------------- You can’t change the wind but you can adjust your sails |
Posted By: WhiteLakeSkier
Date Posted: May-28-2010 at 1:12pm
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No it wasn't sarcastic at all. I trust the source believe me.
I'll get reading, unfortunately no cake in the oven.  ------------- www.correctcraftfan.com/diaries/details.asp?ID=5120&sort=&pagenum=1 - 1961 CC Custom American Skier |
Posted By: 81nautique
Date Posted: May-28-2010 at 1:23pm
Good, you show promise grasshopper. Float adjustment, remove front bowl by loosening the four bowl screws, to prevent spilling fuel all over your intake remove one bottom screw fully and try to catch the fuel in a small cup then wipe any spill with a rag. Remove the bowl, flip it upside down so you are looking at the float. Holding the bowl level, the float should sit level with the top(now bottom because your holding it upside down) if it's not level bend the tab connecting the float to the needle valve with a small pair of needle nose pliers until the float is level. Minor bend is all it should take. ------------- You can’t change the wind but you can adjust your sails |
Posted By: 79nautique
Date Posted: May-28-2010 at 1:24pm
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to check the fuel pressure either disconnect it at the pump out let and attach a hose barb fitting to attach the gauge to or just disconnect the line at the carb and slide the rubber fitting over the line and then check it that way which is typically the easy way to do it. you only need to crank it over for 10-15 seconds to get a reading. I can't see pictures when I'm here at work they get filtered out 95% of the time so excuse me put I can't help you out based on the type of gauge you bought that I assumed you posted.
Regarding the float, check the fuel pressure first, but I feel the float is most likely the issue, but again you have to check the basics first. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: WhiteLakeSkier
Date Posted: May-28-2010 at 1:51pm
Seems pretty level. Do I need to bend it down to make it a bit more level?
Unfortunate I broke the gasket. I assume no napa or anyone would have something like this on hand, so it will be a few days before I can try this out. Now when I pulled it apart, it came a little violently. What does that little brown arm attach to. Am I missing anything in these pictures? I don't see that I lost anything but carb parts are pretty small to spot on top of the engine or elsewhere around the boat.  ------------- www.correctcraftfan.com/diaries/details.asp?ID=5120&sort=&pagenum=1 - 1961 CC Custom American Skier |
Posted By: 81nautique
Date Posted: May-28-2010 at 1:55pm
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It may be the camera angle but it looks a little low to me, I would bend it just a tad more. The little brown piece is fine. Any Napa should have your bowl gasket or can get it from the warehouse pretty quickly. Ask for the blue reusable ones. Also make sure you have the little gaskets on the four bowl screws in place when you put it back together. ------------- You can’t change the wind but you can adjust your sails |
Posted By: WhiteLakeSkier
Date Posted: May-28-2010 at 2:07pm
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Alright, I shall see what I can find at napa. So just leave the brown arm hanging when I put it all back together. The thing looks like it has a purpose, but hey I have seen plenty of pointless engineering. ------------- www.correctcraftfan.com/diaries/details.asp?ID=5120&sort=&pagenum=1 - 1961 CC Custom American Skier |
Posted By: 81nautique
Date Posted: May-28-2010 at 2:08pm
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I didn't see the second photo when I replied the first time. That little brown piece is your metering body vent baffle and it will slip right over the casting boss/pin. It just fell off when you pulled the bowl so yes put it back on the pins. ------------- You can’t change the wind but you can adjust your sails |
Posted By: horkn
Date Posted: May-28-2010 at 2:35pm
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That float does look a tad tow to me as well. The angle of the pic actually makes it look close to level, but if you were to have the bowl completely level in the picture, the float would look even more "low".
Now that copper/ brown piece I am pretty sure just goes to the other "pin" just on the other side of the center that the one side is hanging from. Absolutely napa or other places will have that gasket in stock, and make sure to get the blue ones because those won't stick, and you can reuse them without worrying of them breaking like the original type. If that is a 4 barrel with a transfer tube and single fuel inlet, then you will want to buy a couple o rings for the transfer tube while you are at the store. I would get a new accelerator pump diaphragm as well since you are in there and the front bowl is off. 79, yeah, i did miss a little bit there, but I can say from my own personal experience that as the anti siphon valve gets clogged, it will allow it to rev even at full throttle for a while, then it will just shut off after the restriction doesn't allow the pump to get enough fuel to the bowls. On mine, it progressively got worse and worse after a couple of seasons. when I first got my boat I could go slaloming with no issues. Then the duration it went before acting like it was running out of gas got shorter and shorter. Slower rpm cruising like wakeboarding never gave the motor an issue because the restriction was not enough to go over the amount of fuel demand that was needed for 2100 rpm. eventually that rpm limit and duration of time before it "ran out of gas" got lower and shorter. I figure that was due to more crap getting stuck int he anti siphon valve and it ended up building up a blockage too much to get gas past for more than idling. There were a bunch of bees/ wasps in my anti siphon valve from many years of it never being cleaned. A lower psi pumping fuel pump probably contributed tot he lack of gas delivery too, and I bet the old pump may be needing rebuilding because it wasn't able to get gas into it all the time. I'm guessing no gas in the line won't do anything to help a fuel pump's longevity. Whitelake, you may not have an anti siphon valve, I don't know when that safety measure was added as a factory thing. ------------- 78 martinique- refloored, reinforced, stringers re glassed, re engineered interior GT40P heads Edelbrock Performer intake acme 4 blade http://img.photobucket.com/albums/v64/horkn/fish/nautique.jpg |
Posted By: WhiteLakeSkier
Date Posted: May-28-2010 at 4:11pm
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Just checked the fuel pump. Not sure how accurate the harbor freight tool is, but it read 4 psi. Low I assume? I got the same reading with the screw on filter and without it. It took a bit of looking to find the right gasket at napa, and they wont have it till tomorrow anyways. Not sure if it is the reusable kind, I felt lucky enough to even find it. The catalog he had didnt even have model 4160 in it, closest they had was 4161. Seemed shady but I could tell from the pictures it was the same gasket. ------------- www.correctcraftfan.com/diaries/details.asp?ID=5120&sort=&pagenum=1 - 1961 CC Custom American Skier |
Posted By: 79nautique
Date Posted: May-28-2010 at 4:22pm
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if you have an O'reilley's or Advance parts store they sould carry them too.
new fuel pump marine. Not sure but some model fuel pumps are rebuildable others are disposible. get a new fuel pump, leave the float alone for now, no sence in creating another problem, now if you have moved it all ready leave it for now amd we'll see what happens. but get the new fuel pump installed, reset the idle mixture screws using a vaccum gauge attached to the port for the PCV, engine warmed up and then check base idle while in gear adjust accordingly. Double check your accel pump it should start squirting fluid almost immediately the throttle lever is moved, adjust the nut until it does, if it does seems to help and looks worse then turn it the other way until you get the full stream for the entire stroke of the throttle. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: GottaSki
Date Posted: May-28-2010 at 5:32pm
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Take the entire tank/dip tube assembly apart. I've found clogged cone screens sandwiched between the fittings, mastercrafts have a flexible hose in the tank with a spiral spring that catches and clogs with debris.
There's more out there that can inhibit gas flow than the absent AS valve. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: WhiteLakeSkier
Date Posted: May-28-2010 at 5:51pm
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This isn't a Mastercrap. Just stupid stickers were all over it from the PO. Couldn't I check this by running the engine off a separate tank? I'm not sure how this thing sucks up fuel, but it can't be too complicated. It would be a real pita to get the tank out again and take it out. For sure an idea I'll have to look into though if it runs well off a separate tank.
------------- www.correctcraftfan.com/diaries/details.asp?ID=5120&sort=&pagenum=1 - 1961 CC Custom American Skier |
Posted By: GottaSki
Date Posted: May-28-2010 at 6:19pm
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But, it is a Runslikecrap. for now.
And yes, the secondary fuel source is a very viable troubleshooting technique, as long as it can deliver the volume required for a short period, safely. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: WhiteLakeSkier
Date Posted: May-28-2010 at 6:48pm
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Skidim agreed that the fuel pressure was low. But they also brought up whether or not the secondary diaphragm was working correctly. Possibility? ------------- www.correctcraftfan.com/diaries/details.asp?ID=5120&sort=&pagenum=1 - 1961 CC Custom American Skier |
Posted By: WhiteLakeSkier
Date Posted: May-28-2010 at 6:54pm
Here are some pictures of what it looks like thus far, I never posted any.        ------------- www.correctcraftfan.com/diaries/details.asp?ID=5120&sort=&pagenum=1 - 1961 CC Custom American Skier |
Posted By: 81nautique
Date Posted: May-28-2010 at 7:32pm
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You've come an aweful long way with that boat Michael and you're just around the corner from getting it running the way it should. Hang tough and make sure you're having fun and learning along the way. ------------- You can’t change the wind but you can adjust your sails |
Posted By: GottaSki
Date Posted: May-28-2010 at 7:36pm
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well done indeed!
Now i understand your little mastercraft neurosis. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: GottaSki
Date Posted: May-28-2010 at 7:50pm
I don't think so, just the primaries should be good for 3600 to 3800 rpm. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: WhiteLakeSkier
Date Posted: May-28-2010 at 7:56pm
It has driven me crazy! Removing all the stickers and the rest of the junk all over the place has put me over the edge on Mastercraft. They are nice, just not spread all over a Correct Craft!  ------------- www.correctcraftfan.com/diaries/details.asp?ID=5120&sort=&pagenum=1 - 1961 CC Custom American Skier |
Posted By: horkn
Date Posted: May-28-2010 at 9:12pm
Yeah, the secondaries not working properly won't create an issue like you are describing. An alternate fuel source will let you know if it is from the tank to the pump. If your gauge is accurate, yes, your fuel pump is needing replacement or rebuilding. Just putting a new fuel pump in my CC made it run a lot better. I was getting around 4-4.5 psi tops before the new pump, and afterward I am getting 7 psi. BTW, nice job on the boat so far. ------------- 78 martinique- refloored, reinforced, stringers re glassed, re engineered interior GT40P heads Edelbrock Performer intake acme 4 blade http://img.photobucket.com/albums/v64/horkn/fish/nautique.jpg |
Posted By: akabulla
Date Posted: May-29-2010 at 2:53pm
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That is looking really sharp! Great job!
I can't tell from the picture but it looks like you have single hose clamps on the exhaust. Make sure you double those up! One comes off and water will fill that boat faster than you can shake a leg at! |
Posted By: skicat2001
Date Posted: May-29-2010 at 4:14pm
You have done wonders on that boat. That boat was left for the dead, and you brought her too full life. Great job! Excellent looking boat there..  ------------- 1985 CC 2001-SOLD Lee Michael Johnson |
Posted By: DrCC
Date Posted: May-29-2010 at 9:51pm
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I just can't hold my tongue any longer.
I think you really screwed-up, by not putting that much effort in the old Ski Tique. AT |
Posted By: WhiteLakeSkier
Date Posted: May-29-2010 at 10:30pm
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To each his own. I wanted a better wake, which I got. I wanted a classic, which I got. The boat didn't go to the junkyard, it went to a boat restorer that will bring it back. Do you think I could restore something I didn't have a passion for? I liked this old boat and I wanted to focus my time and funds on making it what I want and nice.
Anyways, Got the carb back together. You were right about the O-rings, I gave it a go and I had gas dripping out of the transfer tube. We'll see how the float adjustment goes when I get some rings. I also ordered a fuel pump since mine tested at 4psi. May not be the solution to my surging problem, but it needed replacing. I got an accelerator pump as well, figure I might as well get a fresh one in there to eliminate the possibility of it screwing with things. ------------- www.correctcraftfan.com/diaries/details.asp?ID=5120&sort=&pagenum=1 - 1961 CC Custom American Skier |
Posted By: DrCC
Date Posted: May-29-2010 at 10:50pm
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I might have the two O-rings.
I'll check. If I do I'll just send them to ya. AT A bad Ballast Resistor can cause some really weird symptoms. |
Posted By: DrCC
Date Posted: May-30-2010 at 2:04am
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Michael, Yes, you are right about the "to each his own"
When I did a Diary search for a 1982 thru 1984 Ski Tique, yours was the only one. AT |
Posted By: 79nautique
Date Posted: June-01-2010 at 11:30am
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get the fuel pump installed then re-adjust all the carb settings and your issue should be gone. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |