rough idle/stall
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=26992
Printed Date: May-20-2024 at 10:37pm
Topic: rough idle/stall
Posted By: Jllogan
Subject: rough idle/stall
Date Posted: July-16-2012 at 11:20am
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ok so Ive got nine hours on the boat since the engine went back in and it has been running great. Idleing perfectly, running strong no problems at all 100%. Towards the end of the day on saturday it very suddenly start idleing rough, it was loping barely hitting 500 rpm on the tach and when you put it in gear it would die. If you kept it revved over 1000 no problems and when you put it under power it stumble til you got it over 1000 and then just take off like a rocket, full power up through the band. You could also tell it was really rich at an idle, mind you this was a sudden change as well, running perfect and then bam next time I slowed down I had this issue and it stayed that way all the way back to the trailer. Any ideas? Could the float be stuck open in the carb and dumping too much fuel in at an idle? ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Replies:
Posted By: GottaSki
Date Posted: July-16-2012 at 11:27am
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Certainly could, though 'stuck open' would be more dramatic, its more likely a peice of crud in one of the needle/seats overfilling the primary or secondary bowl. Could be either or both. Another possibility, though remote, is the PV ruptured. You'll first need to make those visual observations with the SA off while its symptomatic. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: TheChad1976
Date Posted: July-16-2012 at 11:39am
| I am having the same exact problem. I have an 87 with the 351 in it, with the electronic ignition conversion. Engine has 112 hours and I can not get it to idle right to save my life. I've changed plugs, wires, fuel filter, cleaned the anti siphon valve, and even tried to adjust the carb. No Luck. I want to see what others say on here. |
Posted By: Jllogan
Date Posted: July-16-2012 at 11:51am
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yes, you are correct it was a long day and I was tired so I just threw it in the garage and didnt bother looking down the carb yet. Just wanted to make sure I was barking up the right tree. I supposed I could recheck the points/gap but they are only 9 hours old. I feel like that would give me trouble all over though, not just at an idle. Doubt the its the PV first it is also only 9 hours old. Also never backfired, ever, so dont see how it would rupture unless it was just a faulty one. I do have spares though so if I get really stumped I could try one. ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Posted By: 8122pbrainard
Date Posted: July-16-2012 at 12:20pm
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Chad, Have you checked the timing? How about the mechanical advance? Even with the EI conversion, the advance is still mechanical. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Jllogan
Date Posted: July-16-2012 at 12:21pm
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advance wouldn't affect the idle though. if its in time the advance wouldnt affect until revs were up. ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Posted By: 8122pbrainard
Date Posted: July-16-2012 at 12:28pm
It wil if the advance is hanging up and not returning all the way to base timing. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Jllogan wrote:Posted By: Jllogan
Date Posted: July-16-2012 at 12:48pm
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yes but that would cause the timing to read advanced with the timing light. If your base timing is on mark +/- 10TDC then even if the weights were hung up it would still idle ok, it would just be all jacked up when you accelarated. Right? ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Posted By: TheChad1976
Date Posted: July-16-2012 at 12:54pm
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I have not checked the timing yet. I have never messed with timing before so I am "learning" ... Some of the symptoms mine is doing are: *Rough Idle when under a load (in gear wants to shut off) *When you give it gas under load then it gives a chug chug and them jumps up and runs. *If I adjust the idle up to almost 1k it does ok but I don't like it idleing that high. *When I do get idle adjusted right, after I run it around the lake and back it doesn't stay that way (its either too hight again or too low when I come down off plane) *When idle is around 650 - 700ish then it wants to run rough |
Posted By: Jllogan
Date Posted: July-16-2012 at 1:01pm
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ya, you need to check your timing. Thats your base line for your distributors advance curve. You need a timing light and it should be right around 10 degrees at 600 RPM. Rule out that first. ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Posted By: 8122pbrainard
Date Posted: July-16-2012 at 1:04pm
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Chad, When the EI conversion was done, was the timing checked/adjusted? ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: watrski
Date Posted: July-16-2012 at 1:05pm
| I have a spare carb if you need..... |
Posted By: Jllogan
Date Posted: July-16-2012 at 1:07pm
A good working one? Why do you have a spare? ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Posted By: TheChad1976
Date Posted: July-16-2012 at 1:10pm
| I dont know the history of when the conversion was done. (I kind of whish it was still old skool points) The guy I bought it from had just installed a Jasper reman engine and put everything on when he did it. It had 25 hours on engine when when I got it I would assume he checked all of that but it was 3 years ago. It has 112 hours now. |
Posted By: GottaSki
Date Posted: July-16-2012 at 1:30pm
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Chad I suspect you have a vacuum leak and/or the idle fuel orifices are boogared up in the metering block. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: watrski
Date Posted: July-16-2012 at 1:44pm
Last guy that borrowed it....worked fine for him. Spare? I guess so other people can borrow it...never needed it myself ;) |
Posted By: Bri892001
Date Posted: July-16-2012 at 1:49pm
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Justin, One other remote possibility, but a quick easy check. I'm thinking one of your electric choke wires could have popped off, and the choke might have closed up on you. It doesn't make total sense, where you're running fine up top, but chokes are mechanically forced open at higher throttle. |
Posted By: Jllogan
Date Posted: July-16-2012 at 2:08pm
oh brian, nice thinking, ok Ill check that quickly as well, very easy to check and you are correct that would explain how it happened so quickly. also spring inside could have broken. ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Posted By: watrski
Date Posted: July-16-2012 at 2:44pm
is your PCV hose port connected to anything? My local guru had me block it off.
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Posted By: watrski
Date Posted: July-16-2012 at 2:47pm
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PS.... Let me take a pic of mine tonight to make sure I'm not getting the PCV confused with something else. |
Posted By: Jllogan
Date Posted: July-16-2012 at 2:55pm
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mine is a 25 year old carb didnt have those fancy pcv ports back then. Its goes into the spacer. Ill fiddle with it tonight if I have time and see if I cant spot something otherwise, I may just install your "spare" and then Ill know my issue. Plus I need to come over and get some more evening chippewa skiing in, even on your "rough" water. I need a few days for my toe to heal though. ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Posted By: river ratt
Date Posted: July-16-2012 at 11:16pm
i'm having the same issue hard to start and keeping a consistant idle until its ran wide open/cruise for a bit . always having to adjust idle speed up at start then back down. my post was under chug. still not right i'm going to replace fuel pump so i can rule it out. plus a little sea foam .  still falls on its face on a quick start ------------- dont slip on the glass |
Posted By: Jllogan
Date Posted: July-16-2012 at 11:59pm
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seafoam wont help. Are you sure your linkage is tight/adjusted properly? I also doubt its a fuel pump, if anything I would think it would idle ok but then fall on its face when it needed alot of fuel/wide open if the pump was weak. ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Posted By: Jllogan
Date Posted: July-17-2012 at 12:02am
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also I didnt run it tonight but I did rule out the choke. It opened all the way when the element got hot, also the oil smelled a little like gas so that tells me something in the carb is letting too much fuel in again. Its frustrating that it worked great for nine hours, really thought I had it, wonder what changed/happened. I have rebuilt twice in the last year, maybe its time for a new one. ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Posted By: SNobsessed
Date Posted: July-17-2012 at 12:55am
I'm pretty sure that diagram is an automotive carb. If that is what you have, it would be best to get a marine one. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: Jllogan
Date Posted: July-17-2012 at 1:23am
Yes I am 99% no one here has a auto carb, I think the diagram was just for illustration purposes. ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Posted By: GottaSki
Date Posted: July-17-2012 at 11:53am
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I had the orig fuel pump slowly shred bits of red paper gasket into the carb fo.r two seasons before it failed Caused lots of rebuilds inbetween. If you see red sediment in the bowl, jets or needles, that's what it is ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: Jllogan
Date Posted: July-17-2012 at 12:31pm
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Good advice, I dont know how old the pump is, I guess its possible that crap got in it. I have a little filer where the fuel line comes in so that should keep anything from getting through though. Its definitely getting too much fuel at an idle though, I can tell by how its acting and the smell. ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Posted By: 64stang
Date Posted: July-17-2012 at 6:46pm
| Wow, was this timely. I have a 1990 351W PCM with a Holley carb. Last fall it started doing the exact same thing, very rough idle, running flooded would only idle good at 1200 rpm anything below caused loping and flooding, I could not adjust it out. So this spring I attempted to reset the timing with a cheap eBay light and could not get it right. Choke is functioning properly, I replaced plugs, wires, coil, points, condenser, and I also adjusted the air metering screws per instructions. With a new timing light I was able to make the point setup work very good. But when I had the timing issues I ordered a Pertronix Ignitor conversion so I went ahead and installed it. At first it started harder than the points and slightly flooded, otherwise it ran well, but now after maybe 20 hours I can not keep the idle set. At first start unless the idle is set high it will lope and stall, after a while it will be running at 1200 rpm, I then set the idle back and it runs fine for a while, then all of a sudden it will start idling very slow and loping, again I set it up. I am getting ready to reinstall the points. The Pertronix starts harder than the points for sure and I don't like that but I am not sure that the points will solve this. I am starting to think something is stuck or plugged in the Carburetor? |
Posted By: SNobsessed
Date Posted: July-17-2012 at 7:07pm
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Is it possible that one of the idle circuit passages is clogged in the metering block? Maybe it comes & goes with the throttle plate variation covering up the transition slots. I think you can buy the metering block as an individual part, if that is the problem. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: 64stang
Date Posted: July-17-2012 at 11:27pm
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If it is a blocked passage in the metering block, can it be cleaned or flushed out somehow, or is replacement the smart thing to do? Thanks for the help. Mark |
Posted By: SNobsessed
Date Posted: July-18-2012 at 12:51am
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Sure it can be cleaned out - you may have to use a wire to make sure it is open. I only mentioned the replacement because then you know it's good, & wouldn't have to take it apart twice if you missed something. FYI - This root cause is still just a guess on my part! Holley 134-128 - Replacement Metering Block Summit Racing - $46.95 ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: watrski
Date Posted: July-18-2012 at 12:46pm
| There is a point where it just makes more sense to throw your old carb on ebay and replace it with new. |
Posted By: Bri892001
Date Posted: July-18-2012 at 1:03pm
I agree. Or keep it for odds and ends parts, or dissect it for science. Although, it seems like a lot of guys have been fighting crappy brand new needle and seats this season. Not sure if anyone has a good line on the best quality replacements. |
Posted By: 8122pbrainard
Date Posted: July-18-2012 at 1:41pm
When I rebuilt my two Carter YH side drafts, I got the kits from Daytona Parts. The kits came with a proprietary needle and seat that I understand is included in all their kits. Instead of the traditional needle in a hole, their design is a flat rubber against a annular ring. They claim it doesn't plug up. So far so good with my YH's. I wonder if they have a kit for the 4160? ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Bri892001
Date Posted: July-18-2012 at 2:04pm
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Pete, just checked, it looks like Daytona Parts at least lists a kit for Holley 4160s. http://www.daytonaparts.com/findyourcarb.html" rel="nofollow - http://www.daytonaparts.com/findyourcarb.html |
Posted By: Bri892001
Date Posted: July-18-2012 at 3:04pm
I wrote to Daytona through their contact page, asking if they have Holley Kits that include the special valve. They confirmed they do, and wrote back with this:
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Posted By: Jllogan
Date Posted: July-19-2012 at 2:11pm
Yes I am at this point I believe. So for now I borrow a good friends spare, confirm that is the problem and then just get a new one. ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Posted By: GrumpyGeoff
Date Posted: July-19-2012 at 6:22pm
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Hi, what was the end result? We have the same problem, A merican V8 bits are a bit dear over here, particularly with the word marine in front. All the blogs on this forum say the same, timing 10 degrees, yep, done that with a strobe, spot on mechanical advance is working, fitted replacement carb kit complete with needles and seats, swapped primary with secondary seats and needles, no different. This seems to be the most common complaint with Pleasurecraft marine units. Perhaps someone out there who has had these problems and has solved them could give us the diffinitive answer and not just give suggestions that they've read on utube!! MMM i wonder if we could use a Webber and forget the Holly as a water feature in the garden pond mmm think i'll stop now, the red wines going to my head  and the boat's driving me nuts, we just want it on the water and i want it off my drive so i can get in my garage and do my own boat, nice simple ford 1600 powered 120 hp, 14' long and i don't need a 4x4 to pull it or a petrol tanker on the beach, that's why they call me Grumpy Geoff. ------------- ....Don't have children, unless you plan to win the lottery anytime soon!! |
Posted By: Jllogan
Date Posted: July-19-2012 at 6:29pm
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well I think the problem is many people have similar issues but they arent always caused by the same thing. I am going to swap carbs and see if that helps me narrow it down. Once I do I will report back. ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Posted By: GrumpyGeoff
Date Posted: July-20-2012 at 6:28am
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I've had a suggestion from this site to put a low pressure regulator in the fuel line after the pump, 1 to4 psi. I will try that and let you know over the weekend. Cheers Geoff ------------- ....Don't have children, unless you plan to win the lottery anytime soon!! |
Posted By: Jllogan
Date Posted: July-21-2012 at 5:58pm
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Ok so upon further inspection what is happening is fuel is only coming from one side of the carb. When I give it the gas I think the accelerator pump kind of masks the problem but at an idle or low rpm no fuel is coming from the port side. I took apart the carb and was able to shoot carb cleaner through the passage ways. I didn't see anything plugged. Would a vacuum leak cause that to happen? One side have gas and not the other? Seems like the cylinders on the starboard were rich and the port were lean ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Posted By: 64stang
Date Posted: July-21-2012 at 6:12pm
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Hi Jllogan How were you able to determine that no fuel was coming through the port side? I can't see that fuel because of the plates. Would I be able to tell if I screwed the air mixture screw in all the way? Thanks Mark |
Posted By: Oletela
Date Posted: July-22-2012 at 1:38pm
| I had found a re manufactured carb locally at a carb shop and put that on Friday. It is like night and day difference, no hesitation and all she wants to do is go! |
Posted By: Jllogan
Date Posted: July-22-2012 at 2:09pm
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I applied just enough throttle to activated the jets so I could see fuel coming out. It should be dead even. At 1000 nothing was coming from port at 1200 it was just dripping, it really didn't even out until 1500. At that point the engine creates enough vacuum to overpower the leak. Fresh gaskets and I was back in business. Running and idleing smooth now. ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Posted By: Jllogan
Date Posted: July-22-2012 at 2:10pm
It's marine right? ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Posted By: Oletela
Date Posted: July-22-2012 at 2:28pm
| Yes it is, he has several left on the shelf if interested |
Posted By: Jllogan
Date Posted: July-23-2012 at 11:27am
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good deal! We got the boat out and ran it about 5 hours yesterday, no problems so far, ha except I think my neutral safety switch burnt up. So I need to do a little research on the site and fix it. Had to do a little hotwiring on the lake but thankfully I have everything running so well a quick bump of the starter and it was running again. ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |
Posted By: 8122pbrainard
Date Posted: July-23-2012 at 11:33am
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Justin, I'm glad to hear it's running!  For the NSS, get the Ohm meter on it. Take at least one wire off the switch. In neutral you should get a near zero Ohm reading. Fill us in on what you find.------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Bri892001
Date Posted: July-23-2012 at 12:45pm
If you can't see your booster venturis, your choke plate could be the thing that's blocking. Is it opening all the way when it's warm? |
Posted By: Jllogan
Date Posted: July-23-2012 at 12:49pm
righto, Ill do it tonight and report back. ------------- http://correctcraftfan.com/diaries/details.asp?ID=5792&sort=&pagenum=1" rel="nofollow - 1986 Ski Nautique 2001 |