Volvo Penta Stalls in Forward but not Reverse

[Z71Man]

Hi All, I've got a '97 Four Winns with a Volvo 5.7GL and SX drive. The engine had been running reliably this spring and summer but has recently developed a problem.

When taken from neutral to forward gear, the engine sputters and usually stalls. It was possible in some cases to put the lever in forward and quickly add a lot of throttle to keep the engine going, but clearly there's a problem somewhere. Interestingly, the engine goes smoothly into reverse and power can be added slowly without any sputtering or stalling.

The nature of the problem (stalling only in forward, not reverse) suggests to me that it is likely an issue with the drive. Any ideas or similar experiences? Based on searching other threads, it looks as though shift cable adjustment or replacement could be a potential solution, but many of the threads I looked through were related to mercruisers instead of the volvo. I've got a lot more experience with engines than sterndrives...

Any possible repair info appreciated!

 

[Z71Man]

Re: Volvo Penta Stalls in Forward but not Reverse

The more I read about these things, the more it seems like this shouldn't be happening! I'm looking into the ESA system but there seems to be more written about the mercruiser systems than the volvos. What else could make these things run differently in forward vs reverse?

 

[EricKit]

Re: Volvo Penta Stalls in Forward but not Reverse

Hello, I just went through some stalling problems with my Volvo. The idea that it's stalling right when you put it into forward but not if you gas it indicates that the load is barely too much, causing it to stall with the amount of gas it is getting. What is weird is that it doesn't do it in reverse. The cable linking to your gear though may engage reverse a little later in coordination to the throttle, which allows there to be slightly more throttle when you engage reverse than there is when you engage forward.

So what may be happening is where you adjust your idle speed, it's set high enough that when the boat shifts into forward the throttle is still at "idle" causing it to stall. There are several things I'd suggest doing to the boat to fix this before just upping the idle speed. You could (and my manual suggets doing this ever year), adjust the gear linkage or throttle linkage so that they are slightly more coordinated. Another thing you can do is remove your air filter on the carb and run some carb cleaner through it. Also, my connections were corroded where the circular rotating "thing" (I don't know the name) makes contacts to the spark plugs. When I cleaned these contacts I got much better results and stopped stalling actually.

Let me know if you have any questions.

 

[bruceb58]

Re: Volvo Penta Stalls in Forward but not Reverse

The more I read about these things, the more it seems like this shouldn't be happening! I'm looking into the ESA system but there seems to be more written about the mercruiser systems than the volvos. What else could make these things run differently in forward vs reverse?

There is no ESA on a Volvo.

Does it do this in your driveway on muffs? If not, I am betting it is a loading issue becuase a prop has more "bite" in forward than in reverse just the way the prop is designed. The more bite in forward puts on more of a load and causes your engine to bog down more.

What RPM are you idling at? When was the last time you did a complete tune-up?

 

[Z71Man]

Re: Volvo Penta Stalls in Forward but not Reverse

Thanks for the advice guys. The concern over the idle speed was a good one. The last tune up was about a year ago...new plugs, wires, and distributor components.

I ran the engine on muffs yesterday and everything worked fine. It went in and out of both gears with no problems. I checked the idle speed adjust and it was set almost exactly at the point where the throttle was fully closed. I took the distributor cap off and lightly sanded and cleaned all contacts.

When I put the boat in the water, it stalled immediately when I put it in forward. I bumped the idle speed up a small amount and the stalling problem went away. Unfortunately, the tach in the boat is not particularly accurate and I don't have an external tach yet.

I think i'll invest in a vacuum gauge and external tach sometime this fall to give the carb a proper adjustment, but for now the engine is back to being operational.

I wouldn't have thought the propeller load would be that much different in forward vs reverse to cause this problem, but I guess it is. Good advice and I'm sure glad it isn't a drive problem!