Engine stalls after choke opens

Rayfinan

Recruit
Joined
Jul 17, 2010
Messages
5
1977 Bayliner Victoria Command Bridge
Volvo-Penta 8 cyl
Holly 4 barrel

Engine starts runs smooth when choke is closed. After 15 mins or so as choke opens fully engine stalls and will not restart until choke has partially closed again, then will restart and run smoothly till choke opens fully again and dependably stalls.

Has newly rebuilt engine (2009) recently rebuilt holly 4bbl carb, new fuel filter, fuel lines and an electronic fuel pump.
 

aktrucker

Seaman Apprentice
Joined
Aug 3, 2009
Messages
44
Re: Engine stalls after choke opens

Was the origional carb rebuilt, or did you purchase a rebuilt carb? Who did the rebuild, and was anything changed? Only thing I can think of is it's either starving for fuel (lean), or it's jetted lean....either way it I am sure it is a lean condition causing the problem........
 

Rayfinan

Recruit
Joined
Jul 17, 2010
Messages
5
Re: Engine stalls after choke opens

It's a rebuilt carb, the invoice says it was 100% tested and Napa echlin products meet or exceed original equipment. Looking at it and the manual it appears to be exactly right.

Curious that it runs absolutly fine all through till that choke opens fully. And restart only once that choke has close a bit. Takes about 15 mins or so for that choke to fully open would a (jetted lean) condition wait that long to show up?

I ask that because till she stalls she runs like she should.
 

aktrucker

Seaman Apprentice
Joined
Aug 3, 2009
Messages
44
Re: Engine stalls after choke opens

It only stalls once the choke is open, correct? If that is the case then something is causing a lean condition, I bet if you were by the engine when it started to die and partially closed off air with your hand it would continue to run..... I am not as familiar with the Holleys as I am Q-Jets. I am guessing there is idle air screws, or something to adjust the fuel/air mixture at idle?

Have you checked to see what jets are in it, and if the float was properly set?
 

aktrucker

Seaman Apprentice
Joined
Aug 3, 2009
Messages
44
Re: Engine stalls after choke opens

it could also be air leaking somewhere in the intake manifold, carb, base gasket on the carb............that would cause a lean condition, and it might only really rare it's head once the choke opens and allows even more air in. let it idle and spray some starting fluid around tha carb, and the intake manifold gaskets..........don't need to spray a lot, but if any is getting in it will give the RPM's a quick jump.
 

Rayfinan

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Joined
Jul 17, 2010
Messages
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Re: Engine stalls after choke opens

thanks for the insights all. Going out today to check will report later this evening what if anything we discover.
 

TiredoleBoy

Petty Officer 2nd Class
Joined
Jul 11, 2010
Messages
172
Re: Engine stalls after choke opens

1977 Bayliner Victoria Command Bridge
Volvo-Penta 8 cyl
Holly 4 barrel

Engine starts runs smooth when choke is closed. After 15 mins or so as choke opens fully engine stalls and will not restart until choke has partially closed again, then will restart and run smoothly till choke opens fully again and dependably stalls.

Has newly rebuilt engine (2009) recently rebuilt holly 4bbl carb, new fuel filter, fuel lines and an electronic fuel pump.

Sounds like a vacuum leak to me somewhere.
 

fossill

Chief Petty Officer
Joined
Jun 20, 2009
Messages
427
Re: Engine stalls after choke opens

Assuming all vacuum ports are plugged off, use a can of carb cleaner or a can of ether and spray around the base of the carb area and the intake manifold to cyl head area. If you're going to use ether, use it very very sparingly. That cant be stressed enough. If the engine runs good when you spray a particular area you found your vacuum leak.
Off the bat I would suspect the carb to intake manifold gasket. They used to be troubleprone to failure on automotive applications.
 

Rayfinan

Recruit
Joined
Jul 17, 2010
Messages
5
Re: Engine stalls after choke opens

"Assuming all vacuum ports are plugged off, use a can of carb cleaner or a can of ether and spray around the base of the carb area and the intake manifold to cyl head area. If you're going to use ether, use it very very sparingly. That cant be stressed enough. If the engine runs good when you spray a particular area you found your vacuum leak.
Off the bat I would suspect the carb to intake manifold gasket. They used to be troubleprone to failure on automotive applications. "

Will be trying this, I guess you mean if there is a surge when the leak is sprayed because till lt quits it runs great.
 

fishinpa

Petty Officer 1st Class
Joined
Nov 2, 2009
Messages
221
Re: Engine stalls after choke opens

If there is a leak and you hit the area with the spray /

what they are stating is that

you will hear a difference in engine speed !

then you will have found the trouble area - if it is a leak and not an internal carb problem or other.


fish
 

Rayfinan

Recruit
Joined
Jul 17, 2010
Messages
5
Re: Engine stalls after choke opens

On boat today, found a log of the guy who sold me the boat. Dated early May ( I bought it last week of june)it logged several tow's in a day, and outlined the suddenly stalling not being able to restart.

He assurred wife & I when I bought it she was capable making it to sacto from san rafael. That everything worked other than no reverse(outboard kicks up in reverse) all else was in good mechanical condition.

He started it up, ran it for a minute or two revved it a couple times it sounded great we bought the boat knowing we'd have to get her pulled soon and the rear locking mechanism repaired.

As we left that day the seller said he'd put a new fuel filter in for us since there seemed to be a shudder @ 8 knots and pilot it back to sacto (as I am a virgin on the water) As I insisted that I go along when it happenned ,to learn, he kinda paled but I didn't register that till he started dodging the calls.
Because it was a auxillary coast guard volunteer youth scout boat, I had to get it registered and new cf numbers before I could take it out, no problem, done the next day.

3 days later he returns calls, filter not done yet. Before I can get a certified mechanic on the scene he pulls the carburator, tells me he's getting a rebuilt one on his dime.

After one excuse or another and 3+ wks a friend and I went to inspect the boat two days ago.

Today, we had her purring for over an hour we decided between the small tightening the carburator to torque specs and the quick restarts (2) after hour plus running we were good. We also inserted a fuse and switch inline to a jimmy rigged electronic fuel pump.

We were told day before had plenty of gas, the fuel gauge had been removed before I bought it. However later before when she stalled my car mechanic friend touched the electronic fuel pump said it was getting hot and probably because of no fuel. We added the fuel and she again ran long enough with rests after choke fully openned to determine the open choke problem.

We put in 9 gallons yesterday and ran it a total maybe 1.5 hour. Today after letting her run for an hour+, needing to ensure there was gas, the gas dock only 100 yards away, we go to get gas thinking if no issues we go on further turning the corner we got 25 yards or so when the famous stall occurred.

We tied to a slip accross the way from the original slip ,waited to get towed by the harbor police. Before calling them we got 5 gallons of gas,tried a dozen or more time to start to no avail,even when choke completely closed)

As they pulled us out of the slip an officer noticed quite a bit of gas flowing around the boat on the water. As I voiced a concern of what could have occurred he said may have come out of the exhaust due to flooding (okay , maybe I was a tad energetic).

Seems like a lot of gas and coming out the exhaust? She never started again. Always sounded like she wasnt getting any gas so I start thinking gas tank leak, maybe vapor lock due to leak, from what I've read it might explain the stalling as well. Turning over almost catching sounded fuel starved. No heavy smell of gas in the boat no obvious leaks inside compartment and weak squirts in the carburator.

Small puddle under engine passed a smell, test no gas there.

checked access in center ship dry there no smell of gas.

Could a leak in the tank cause anything like this and or how could it leak out unseen? Did notice bubling sound port side of bow while waiting tow.

Any insights be greatly appreciated.
 
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