volvo penta 5.7GL stalls

[gatorscott]

History, engine rebuilt over a year ago, carb rebuilt one year ago, replaced fuel line this weekend tested with fresh, ethanol free gas. Volvo penta 5.7, 1998.

Engine starts normally. Will run for 15 to 25 minutes and then stalls. Engine immediately restarts, no problem or issue. Engine will then stall again within a few minutes. Will immediately restart with no problem. Engine will stall again and restart with each subsequent stall ocurring in less and less period of time.

The engine does not backfire, just quiety stalls. A faint puff of light grey smoke exits exhaust near prop. Boat runs fine when up on plane and RPMs over 2500-3000. Seems to idle fine except for stalls. Never has an issue immediately restarting.

No water in gas. Have replaced fuel filter, fuel line, tested with fresh marine fuel, engine was rebuilt as was the 2 barrell holley 2300 carb. Carb was in bad shape, mechanic soaked it in acid for a day. Stalling still happens with fuel filler cap removed.

Boat has had this feature since then, so am assuming the carb is my problem. Fuel pumps seems to be fine as it pulled from the test container and fuel tank fine after changing the fuel line. How can I test or confirm? Could it be anything else? What am I missing?

I am by no means a mechanical guru. I can do some things myself, but don't know the innards or terminology of a carb, but am willing to learn.

 

[mikeneal]

Re: volvo penta 5.7GL stalls

Def sounds as if fuel issue as my 1st guess. Perhaps a intermittent fuel pump failure. I once wired an indicator light to fuel pump circuit to troubleshoot an indeterminate fuel system, problem. Post your full serial number and Don S. will point you to a factory manual with tons of good info (including wiring diagrams)

 

[Don S]

Re: volvo penta 5.7GL stalls

If it's a fuel problem, I would start by doing these tests and watch the gauge when the problem occurs.
http://forums.iboats.com/showthread.php?t=283269

 

[gatorscott]

Re: volvo penta 5.7GL stalls

Thanks for the replies...

If it was an intake problem from the tank, it would not have had the same issue when i put the fuel line in a red, 5 gallon container of fresh marine gas. That would eliminate gunk in the main fuel tank and a possible pickup or filter issue. It would not eliminate a fuel pump or carb issue.

Can you put a 4 barrel carb on this engine? It came with a 2 barrel holley marine 2300. What is the advantages/disadvantages of going 4 barrel? Do I need a new intake on a SB 350?

What are the opinions on Rochester/Edelbrok/Holly carbs?

I am thinking this is a carb issue since the pump was able to pull gas, seemingly fine, from the 5 gallon container with an empty fuel line. I know i am making some assumptions, but even if so, replacing a fuel pump is under 100.

I still plan to do the fuel and vacuum metering... just looking at all options.

 

[gatorscott]

Re: volvo penta 5.7GL stalls

I have checked out the entire fuel system... had a Holley carb guru check out the carb... and the problem still persists. No fuel pump or vaccum issues were noted, carb is not flooding nor starving the engine. Carb guy thinks a possible electrical problem.

What in the electrical system could cause this? Ignition coil? Distributor module?

He also theorized about a possible heat/temperature switch that is killing the engine as if it was overheating. Does that exist? It almost makes sense because it stalls more frequently when it is warm. BUt it does NOT stall when at high rpm so that may disprove that theory.

Anyone have any more thoughts/ideas?

 

[Don S]

Re: volvo penta 5.7GL stalls

There are no switches that will kill the engine for any kind of reason. Even EFI engines with ECM's only bring the engine down to a lower rpm, they NEVER shut them off completely. Even if 0 oil pressure is showing.

IF the fuel system is ok, I would suspect the carb. Many, Many carbs that have suffered with corrosion are not rebuildable. Problem is, the only way to find out is by trying. If it doesn't work, get a new carb. There are to many small passages that can plug up in a carb, that just can't be cleaned out so they will work properly. I'm afraid you have one of those.