1992 volvo penta 570A hesitates

[sseuf]

engine hesitates/stumbles when i'm trying to pull a skier out of the water. helps if i start out in gear but still have to be very slow and smooth with the throttle or the engine quits. is there any common problem with this engine such as spark advance, carb accelerator pump, fuel delivery problem where i should start looking? once i get going the engine runs great.

 

[Maclin]

Re: 1992 volvo penta 570A hesitates

When did this start?
When was the last full tune-up (fuel filter, cap, rotor,spark plugs, maybe spark plug wires)?
Does it run hot?
When was the carb last gone thru?
How old is the gasoline, if not fresh was it treated before layup?
Any other recent symptoms?

The 570's respond to tune-ups or lack of same just like any other engine, nothing peculiar just to them.

If I had to go on just what you have mentioned, which did not include a recent tuneup, then I would change cap and rotor and spark plugs with good OEM sourced stuff. I would change the water separator/fuel filter. I would also have the carb rebuilt to stock specs. That should cure it.

 

[sseuf]

Re: 1992 volvo penta 570A hesitates

hesitation has been an intermittent problem over the past few years. adding a bottle of techron seems to help. a tuneup was done last year and that seemed to help alot but now the problem is persistent again. the resistance of the spark wires is fine and i don't see any arcking when i open the engine cover at night. the engine runs consistently at about 160, well at least until the sea water impellor went (see my other post). based on the paint i would say the carburetor has never been off the engine. the accelerator pumps give a good stream tho and like i said it runs fine other than the hesitation. before the tuneup last year it was backfiring occasionally when it hesitated.

not sure there is anyone in my area that still works on carbs - do you know if volvo sells a rebuild kit for the 570a and does it include seats and jets and can a mere mortal adjust the carb linkages or does it requie a flow meter or other specialized equipment? if not is there a place i can send the carb to get it rebuilt? does ethanol in the gas cause any problems with this engine?

i always add stabilizer to the fuel before the boat is stored for the winter. i'll change the fuel/separator and clean and gap the plugs and see if that helps and check the rotor and cap.

 

[Maclin]

Re: 1992 volvo penta 570A hesitates

The Holley carbs have some rubber diaphragm pieces that do not last forever. The accelerator pump uses one, the powervalve is another part that uses one. Both of those items affect the holeshot.

I have never tried to look up a carb kit from Volvo for this. I redid mine but I have 20+ years of experience with Holleys and I knew what carb kit had most of what I needed for gaskets and needle and seat and other parts. I had to buy the power valve separately as the one in the kit is not what is in the carb. If you are not familiar with Holley carbs then this may not be the carb to learn on. It is a bit different than most vacuum secondary Holleys as it uses a secondary metering block but is not a "double pumper" so it has no secondary powervalve or accelerator pump or idle circuits.

If the carb has never been apart then it still has the factory cardboard gaskets, those are a major pain to get scraped off. I would recommend finding a Holley experienced person to work on it. If they are not familiar with Marine engines they may try to re-think how the carb should be tuned, so warn them not to. Just lean on them to find and put back in the correctly rated powervalve as the one from a kit will almost surely not be the correct one, power valves are available separately. Also insist they not stray from whatever jet sizes are in there and leave the squirter sizes alone and accelerator pump cam as is. The carb is setup a little different from a typical street engine of that size and they may think they know better about what the engine needs. Trust me, the carb as it came from Volvo is what the engine needs!