Forums
NautiqueParts.comNautiqueSkins.com - Correct Craft Upholstery and Part
  New Posts New Posts RSS Feed - Possible 176 Carb issue
  FAQ FAQ  Forum Search   Register Register  Login Login

Possible 176 Carb issue

 Post Reply Post Reply   
Author
ETALLEN View Drop Down
Groupie
Groupie


Joined: July-25-2017
Location: Greenback tn
Status: Offline
Points: 83
Post Options Post Options   Thanks (0) Thanks(0)   Quote ETALLEN Quote  Post ReplyReply Direct Link To This Post Topic: Possible 176 Carb issue
    Posted: July-16-2019 at 10:58am
Everyone has been amazing with the help so i figured i would try my luck again before my engine guy gets back in town .

The 176 has been a blast, no issues and i thought everything was perfect until last night(might not be a major issue but i need to ask those in the know)

While cleaning the boat after running it for 2.5 hours last night i opened the cowl to check fluid levels and make sure nothing was wrong. it was dark so i had a headlamp on, after looking things over i started to lower the cowl when the light hit a small (size of the head of a thumb tack) extra shinny spot. Right below the front of the carb on the intake manifold.

I propped the cowl back up, grabbed the LED shop light, some shop towels and a dental mirror trying to find the source. Spent a hour+ trying see a leak anywhere. Bottom of the carb bowl was dry and clean when wiped with a shop towel,Bottom accelerator pump clean and dry as well. When the spot was cleaned off the manifold it was a medium brown, slightly oily but thin like gas. Smelled like gas but not strong like fresh gas would be.(Sorry im not a engine guy, this must be what the girlfriend feels like when i ask her to measure something for me)

If i remember correctly i remember seeing a extra shinny spot in the same location when i bought the boat but by the time i made it home it was gone and was not there when my friend did a inspection of the motor(engine builder) , and have not seen it in the 15+ hours of run time until last night. I am fairly diligent with checking things over before i go out and when i put it back into the garage . I am thinking possible drip at one of the small o-rings on the fuel bowl ? maybe ?   
Just throwing this out there, my engine guru is out of town until the 23rd, I want to be safe, but i would like to put my mind at ease/use the boat in the mean time.
the final price is always cheaper when the beer is free
Back to Top
KENO View Drop Down
Grand Poobah
Grand Poobah


Joined: June-06-2004
Location: United States
Status: Offline
Points: 10604
Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: July-16-2019 at 1:10pm
Maybe any of the below

one of the O rings for the bowl screws/bolts

Accelerator pump diaphragm

One of the fittings where the fuel line attaches to the bowl

One of the casting plugs on the bowl

Not being sure of the location, a bit farther back it could be the bowl to metering block gasket.

Not too likely, but a cracked or porous bowl

Back to Top
91NaughtyQ View Drop Down
Senior Member
Senior Member
Avatar

Joined: July-27-2015
Location: NC
Status: Offline
Points: 287
Post Options Post Options   Thanks (1) Thanks(1)   Quote 91NaughtyQ Quote  Post ReplyReply Direct Link To This Post Posted: July-16-2019 at 1:18pm
I had the same problem and you really wont see or feel the leak unless there is fuel pressure while the boat is running. Mine turned out to be a simple tightening of the screws on the bowl. It is gas you are seeing, but I guess it gets to look like that after grilling on the engine while running. Check those four bolts at the bowl and CAREFULLY tighten them if they are loose. If you are heavy handed you can break them off. (Don't ask how I know)
1991 Ski Nautique
(Previous)1984 Ski Nautique 2001
Back to Top
ETALLEN View Drop Down
Groupie
Groupie


Joined: July-25-2017
Location: Greenback tn
Status: Offline
Points: 83
Post Options Post Options   Thanks (0) Thanks(0)   Quote ETALLEN Quote  Post ReplyReply Direct Link To This Post Posted: July-16-2019 at 3:06pm
Thanks for that option, definitely will check the bolts this evening. Probably should have checked them before posting. Will try to avoid gorilla-ING the bolts(I to am heavy handed). Fingers crossed it could be that simple
the final price is always cheaper when the beer is free
Back to Top
ETALLEN View Drop Down
Groupie
Groupie


Joined: July-25-2017
Location: Greenback tn
Status: Offline
Points: 83
Post Options Post Options   Thanks (0) Thanks(0)   Quote ETALLEN Quote  Post ReplyReply Direct Link To This Post Posted: July-22-2019 at 1:09pm
Update,

Attempted to tighten up bolts, no forward progress. Ordered a rebuild kit(for spring of next year) and the blue reusable bowl gaskets.

Pulled off the bowl, cleaned the surfaces and installed the new gaskets. No leaks in 3 hours of run time . Bowl was not to bad but both gaskets were shot, fingers crossed the rest hold up this season.

appricate all the help
the final price is always cheaper when the beer is free
Back to Top
brantb View Drop Down
Groupie
Groupie


Joined: May-15-2019
Location: Colorado
Status: Offline
Points: 94
Post Options Post Options   Thanks (0) Thanks(0)   Quote brantb Quote  Post ReplyReply Direct Link To This Post Posted: July-22-2019 at 1:18pm
What rebuild kit did you order? I will be rebuilding mine this fall. I dont think my secondaries are opening so going to see if i can get a new diaphragm locally, but might just order a rebuild kit now if it comes with one.
Back to Top
KENO View Drop Down
Grand Poobah
Grand Poobah


Joined: June-06-2004
Location: United States
Status: Offline
Points: 10604
Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: July-22-2019 at 1:24pm
If you look at your list number on the choke air horn, you can use that number to get the right rebuild kit.

Some kits have the secondary diaphragm, some don't.

Here's a picture of where to find the list number

Back to Top
KENO View Drop Down
Grand Poobah
Grand Poobah


Joined: June-06-2004
Location: United States
Status: Offline
Points: 10604
Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: July-22-2019 at 1:28pm
Click on the link below for some info on Holley secondaries and how to see how far they open

link
Back to Top
ETALLEN View Drop Down
Groupie
Groupie


Joined: July-25-2017
Location: Greenback tn
Status: Offline
Points: 83
Post Options Post Options   Thanks (0) Thanks(0)   Quote ETALLEN Quote  Post ReplyReply Direct Link To This Post Posted: July-28-2019 at 9:50pm
Well tightening up the bolts solution was a good one ,but unfortunately it was not a permanent solution. Yesterday while out on the water got a strong fuel smell, popped the cover and the day was over.
Accelerator pump had a slow drip. Figured it was time to address the bowl gaskets.
Cleaned everything well, replaced power valve, gaskets and accelerator pump. Easy enough right(?) Nope runs like crap and stalls out. Back apart to see if I missed anything, couldn't find anything wrong. Even tried reusing the old power valve no change.   Adjusted carb back to factory settings,( 1 1/2 turns out) no change- actually seems to be worse.
Linkage at accelerator pump is adjust per instructions.
What am I missing?? Should I look into fuel/water separator?
I'm completely lost
the final price is always cheaper when the beer is free
Back to Top
KENO View Drop Down
Grand Poobah
Grand Poobah


Joined: June-06-2004
Location: United States
Status: Offline
Points: 10604
Post Options Post Options   Thanks (1) Thanks(1)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: July-28-2019 at 10:56pm
Take a look at the picture below and you'll see the transfer tube for the accelerator pump right above the power valve. It has a small O ring on each end and if one of those is missing or damaged the engine will run real rich and idle lousy. In the picture one O ring is missing.

That tube is a pretty tight fit into the metering block and the carburetor body and the O rings can get damaged or broken when coming apart or reassembling.

It might be worth a look if your engine is running really rich at idle, you didn't say if it's rich, lean or not sure.

If you click on the link you'll find the thread this picture came from, it might help

I wonder what ever happened to KooK?

link



Back to Top
ETALLEN View Drop Down
Groupie
Groupie


Joined: July-25-2017
Location: Greenback tn
Status: Offline
Points: 83
Post Options Post Options   Thanks (0) Thanks(0)   Quote ETALLEN Quote  Post ReplyReply Direct Link To This Post Posted: July-28-2019 at 11:05pm
The tube is stuck in the carb body, and the o ring is brittle . Definitely rich

Guess that's what I get for only attempting to change out the leaking gaskets.

Tomorrow I will be removing the whole thing and doing a complete tear down/cleaning. Ultrasonic bath followed up a complete rebuild kit.

Fingers crossed no other demons show up
the final price is always cheaper when the beer is free
Back to Top
ETALLEN View Drop Down
Groupie
Groupie


Joined: July-25-2017
Location: Greenback tn
Status: Offline
Points: 83
Post Options Post Options   Thanks (0) Thanks(0)   Quote ETALLEN Quote  Post ReplyReply Direct Link To This Post Posted: August-04-2019 at 12:16pm
This post has dragged on for a while, unfortunately I don't see a end in the near future because my mechanic myself are completely stumped

Finally had time between work and family to tear into the carb.   Installed the Holley rebuild kit to the T, attempted to start boat->pouring fuel out of secondary vent tube. Carb back off, Checked the float, its set perfectly,   On and off 3 more times, finally checked needle and seat and found a issue. New needle is almost a light 1/8" short than the old one.
Swapped old needles back into carb ,fuel no longer leaking from vent.

Get it running decent at idle on trailer get idle set and seems fine.
Back off trailer and it starts to bogging down and has a decent amount of hesitation. Back to vacuum testing and adjusting , just when I think it's right in gear at idle the moment any additional load is added it loads up and feels like I'm dragging a pallet of concrete across the lake floor. Accelerator pump adjusted per instructions and fuel is being spurted when accelerated.

When night finally hit and it was to dark to do anything we pulled it out and dragged it home, pulled the carb off and did a spot check to see if we missed anything. Previous post showed the accelerator pump tube with a o-ring on it, when I tore into the carb last night the o-ring was slightly ripped, and basically flush with 3/4 of tube. Could this be causing all my problems? At one time the mixture screws were adjusted 3/4 out to get the correct amount of vacuum. It acts like it's running rich the entire time, any amount of throttle over 2500rpm loads the carb of with fuel causes a hesitation and flowed by a small backfire.

I'm really stumped, going to the new o-ring on the accelerator pump tube and put in a new power valve because of the backfire last night.
Fingers crossed this is it.

the final price is always cheaper when the beer is free
Back to Top
KENO View Drop Down
Grand Poobah
Grand Poobah


Joined: June-06-2004
Location: United States
Status: Offline
Points: 10604
Post Options Post Options   Thanks (1) Thanks(1)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: August-04-2019 at 2:47pm
Your carburetor is new enough that it has the power valve protection mod as a standard feature assuming it's what came on the engine originally.

If the O ring isn't sealing, there's a direct flowpath for fuel into the manifold without any real metering except for the clearance between the tube and the hole it fits into in the carburetor body.

It seems like the original problem was some small weeping/leak and what you've done has made things worse, so you should be able to undo it and be running good again
Back to Top
ETALLEN View Drop Down
Groupie
Groupie


Joined: July-25-2017
Location: Greenback tn
Status: Offline
Points: 83
Post Options Post Options   Thanks (0) Thanks(0)   Quote ETALLEN Quote  Post ReplyReply Direct Link To This Post Posted: August-04-2019 at 7:09pm
Thanks for the info Keno.

This project has taught me a whole new form of patience. After replacing the damaged o-ring and reinstalling the carb the front primary vent started dumping fuel while cranking . Guess the o-ring allowed enough fuel to bypass the metering plate hiding the float being out of adjustment. To make matters even more frustrating the battery decided to give up the ghost .   With all this bad vodoo going on I figured that should check every other thing that could bite me in the butt before I made another trip to town.. Most things all looked up to par but when I started pulling plugs all I could do was laugh.

The plugs were a Bosch variant, and they appeared to have been in the boat for most of it's life. The ground electrode was burned halfway through, and the center electrode resembled a needle more than anything else.   Surprisingly I never felt a lack of performance. All of these issues have me really questioning the PO maintenance schedule if any. While I was out chasing down a battery I grabbed a full set of spark plugs, autolite-24. Reading the manual it says .045" is the gap, is that still recommend amongst those in the know?

First the float height using the upside down and level method , 2nd time I used the gauge that comes with the Holley rebuild kit and set it 1/16 above level,. Should I go another 1/16 or go big at 3/16? Pulling the carb off to get the bowl off is a pain, if there is some magic float height setting for this carb I would be in forever in your debt.

Battery has been acquired but the two closet ramps are a mad house between 11-5 on Sunday. Looks like I'll either be pulling a late evening testing or one night this week. Two weekends not on the water is starting to make me loose what little sanity I have left
the final price is always cheaper when the beer is free
Back to Top
KENO View Drop Down
Grand Poobah
Grand Poobah


Joined: June-06-2004
Location: United States
Status: Offline
Points: 10604
Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: August-04-2019 at 11:01pm
The picture below shows what seems to work good with a 15 degree engine angle with the Borg Warner transmissions.

Since your 176 has a more level engine with the 1.23 to 1 transmission, I don't think I'd go any more away from level than what the picture shows or maybe 1/8 inch at most



Are you sure the front needle is the right length and not short like your back one was?

With the standard electronic Prestolite if your manual says .045 then go with that.
Back to Top
ETALLEN View Drop Down
Groupie
Groupie


Joined: July-25-2017
Location: Greenback tn
Status: Offline
Points: 83
Post Options Post Options   Thanks (0) Thanks(0)   Quote ETALLEN Quote  Post ReplyReply Direct Link To This Post Posted: August-04-2019 at 11:06pm
After the back needle debacle I put the original needle back in the front. Thankfully I still had them separated out on the work bench. It's now set at 1/8".
If weather and my work schedule cooperate I will try to dunk the boat and fire it up tomorrow.
I appreciate all the help,
the final price is always cheaper when the beer is free
Back to Top
KENO View Drop Down
Grand Poobah
Grand Poobah


Joined: June-06-2004
Location: United States
Status: Offline
Points: 10604
Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: August-04-2019 at 11:09pm
Good luck
Back to Top
ETALLEN View Drop Down
Groupie
Groupie


Joined: July-25-2017
Location: Greenback tn
Status: Offline
Points: 83
Post Options Post Options   Thanks (0) Thanks(0)   Quote ETALLEN Quote  Post ReplyReply Direct Link To This Post Posted: August-07-2019 at 11:09am
Finally have the boat up and running again.

Hard to believe that the small o-ring on the accelerator tube could hide a incorrectly adjusted float height, KENO you are the man!

Used my vacuum gauge hooked up to the hole located on the intake manifold behind the carb.   Best amount of vacuum that i could get that was steady at idle(760prm) in neutral was right around 18 on the gauge- in gear at idle (700rpm) 14 on guage. Throttle response is better than ever and idle is very smooth.

One concern i have is the mixture screws are out 1 1/4 turns from seated, I did not have much time to run the boat under load, 10-15 minutes at most. Just want to make sure that i am not running the motor to lean --> running a risk of harming the engine. I did keep a eye on the temp and oil gauges and all seems normal. After the last adjustment the boat ran 10-15 minutes while i stowed everything away,

I will be pulling the plugs periodically to check them. just thought i would ask before I got the boat back out on the water.

Motor is PCM 5.8
Carb Holley 4160 idle mixture screws currently set at 1 1/4 out


This picture show how bad the carb was. I dont believe i was getting anything out of the secondaries , the body of the carb on the secondary side was even worse.

Thanks again for all the help and info
the final price is always cheaper when the beer is free
Back to Top
phatsat67 View Drop Down
Grand Poobah
Grand Poobah


Joined: March-13-2006
Location: Indiana
Status: Offline
Points: 6147
Post Options Post Options   Thanks (1) Thanks(1)   Quote phatsat67 Quote  Post ReplyReply Direct Link To This Post Posted: August-07-2019 at 11:24am
Good work. The idle mixture screws control nothing but idle mixture. There rest of the mixture is set other parts of the carb and you won't run lean anywhere but idle if it is lean or rich etc.
Back to Top
Jonny Quest View Drop Down
Grand Poobah
Grand Poobah
Avatar

Joined: August-20-2013
Location: Utah--via Texas
Status: Offline
Points: 2822
Post Options Post Options   Thanks (1) Thanks(1)   Quote Jonny Quest Quote  Post ReplyReply Direct Link To This Post Posted: August-07-2019 at 11:54am
Originally posted by phatsat67 phatsat67 wrote:

Good work. The idle mixture screws control nothing but idle mixture. There rest of the mixture is set other parts of the carb and you won't run lean anywhere but idle if it is lean or rich etc.


+1

As Phats said, the idle mixture screws name implies -- they only control the air/fuel mixture at idle. The throttle valve should be closed at idle and the carb runs on the idle circuit. You adjust your idle mixture screws to achieve maximum vacuum at idle. I've seen screws out as little as 1/2 turn and as much as 2 1/2 turns from lightly seated.

If you are concerned about running too rich or too lean above idle, you can tweak that also. Your rich/lean setting on the primary circuit is mostly determined by your jet size and power valve. If you hear detonation, you are too lean and/or have too much timing advance. If you don't hear detonation, you can pull your spark plugs after several hours and "read" them for signs of too rich or too lean. Lots of information on Google about reading spark plugs.

Also, nice job on troubleshooting the carby. An ill-behaved carby can be frustrating to work on.

JQ
Current
2003 Ski Nautique 206 Limited

Previous
2001 Ski Nautique Open Bow
1994 Ski Nautique Open Bow

Aqua skiing, ergo sum
Back to Top
KENO View Drop Down
Grand Poobah
Grand Poobah


Joined: June-06-2004
Location: United States
Status: Offline
Points: 10604
Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: August-07-2019 at 4:27pm
Originally posted by ETALLEN ETALLEN wrote:


Hard to believe that the small o-ring on the accelerator tube could hide a incorrectly adjusted float height, KENO you are the man!


Nah, you're the man, you did all the work.

I'm just a young kid who's first toy's were a carburetor and a distributor   

The carburetor was a Carter YH that leaked like a sieve. I managed to conquer that and moved on to other brands.

The distributor had a clapped out set of points that I had to learn to clean and adjust

But anyways..................a wise old guy told me a lot of years ago "Kid, if you want to keep stuff running good, get to know fuel and ignition systems"
Back to Top
KENO View Drop Down
Grand Poobah
Grand Poobah


Joined: June-06-2004
Location: United States
Status: Offline
Points: 10604
Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: August-07-2019 at 10:16pm
Originally posted by Jonny Quest Jonny Quest wrote:

[QUOTE=phatsat67]

Also, nice job on troubleshooting the carby. An ill-behaved carby can be frustrating to work on.

JQ


What happens after you get too frustrated JQ ?

Do you give up and go out and buy a new Quick Fuel and decide it's the best thing since sliced bread?
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Copyright 2024 | Bagley Productions, LLC