Volvo Penta 5.7 acceleration

bearlys2005

Cadet
Joined
Jun 28, 2010
Messages
6
I?m having problems with full throttle starts and top end on my Volvo Penta GSI 5.7. The outdrive is an SX-M 1.51 (3868698) running a stainless prop which is 17 pitch I think. This is our second year with this boat and the problem has just started.
From an idle if you full throttle it pretty much falls on its face. Won?t even begin to get the boat up on plane, it also makes a bogging sound until you let up on the throttle. If you take off easier it will come up on plane and getting to 30/33 or so it seems fine. At about 35 the sound starts to come back and the further you push the throttle the worse it gets. Also for the full story a few weeks ago the boat was on the water for the weekend during a storm with the batteries turned off (my mistake). When I got on the boat the next day and switched on the batteries the bilge pump ran for quite some time. We loaded the boat on the trailer and took it home and parked it in the building. The next time we got the boat out (2 wks) all this started happening. Not sure what the deal is with this so I thought someone might have some insight and be able to point me in the right direction.
I do all the work on all my equipment. This is what has been done to the boat thus far. Pulled the fuel filter and drained it into a pan to allow separation. Found some water in the fuel so I added dry gas as well as fresh fuel. Checked fluid in the outdrive which was fresh for the season, it is still fresh and not creamy. Pulled the outdrive and there was a little water in the upper bellows but nothing excessive. I checked the u joints which seemed fine so I greased them as well as the shaft. I then cleaned and dried the bellows then checked the gimbal which was also fine. Greased the gimbal and re-installed the outdrive. Sorry if this is long but wanted to let everyone know what?s been done.
Paul
 

sqbtr

Senior Chief Petty Officer
Joined
Feb 23, 2010
Messages
716
Re: Volvo Penta 5.7 acceleration

Coud be moisture related, did you check the distributor cap?

I sure would run a dedicated fused circuit to the bilge pump so even with the batts off the pump will run
 

bearlys2005

Cadet
Joined
Jun 28, 2010
Messages
6
Re: Volvo Penta 5.7 acceleration

Coud be moisture related, did you check the distributor cap?

I sure would run a dedicated fused circuit to the bilge pump so even with the batts off the pump will run

Yes I already took care of that bilge pump problem... We normally don't leave it on the water because we travel with it to different places so I never really thought about it. I'll check for moisture in the cap and everywhere for that matter.
 

whit71

Seaman Apprentice
Joined
Jun 23, 2010
Messages
46
Re: Volvo Penta 5.7 acceleration

Is this a carb or fuel injected? How old was the gas in the tank? Could be another victim of Ethanol!!
 

bearlys2005

Cadet
Joined
Jun 28, 2010
Messages
6
Re: Volvo Penta 5.7 acceleration

Is this a carb or fuel injected? How old was the gas in the tank? Could be another victim of Ethanol!!

The engine is a 1999 fuel injected. Part of the tank was old (less than half) and I have added dry gas plus filled up with fresh fuel. What happens with Ethanol? It may be 10% I really didn't pay attention at the pump.
 

whit71

Seaman Apprentice
Joined
Jun 23, 2010
Messages
46
Re: Volvo Penta 5.7 acceleration

The alcohol which is what ethanol is attractes moisture and if it sits for an extended period of time can cause problems in fuel system. Im sure somebody on this forum will correct my simplified explanation of the problems with ethanol. Bottom line if you can find a gas station in your area that sells ethanol free fuel.
 

bearlys2005

Cadet
Joined
Jun 28, 2010
Messages
6
Re: Volvo Penta 5.7 acceleration

The alcohol which is what ethanol is attractes moisture and if it sits for an extended period of time can cause problems in fuel system. Im sure somebody on this forum will correct my simplified explanation of the problems with ethanol. Bottom line if you can find a gas station in your area that sells ethanol free fuel.

Well I'll keep and eye out for that... Never really thought about that one.
 

bearlys2005

Cadet
Joined
Jun 28, 2010
Messages
6
Re: Volvo Penta 5.7 acceleration

Well I did some work on the boat last night and found that the plugs, cap, and wires are original to the boat... Now the boat only has 87 hours on it but it is a 1999 so the parts are better than 10 years old. Two of the plugs were not firing or firing correctly which I'm sure the computer picked up on. The original plugs weren't even marine grade so i replaced all of them with the correct plugs plus I replaced the cap a wires. It runs great on the hose but the true test will be when I put her on the water...
 

bearlys2005

Cadet
Joined
Jun 28, 2010
Messages
6
Re: Volvo Penta 5.7 acceleration

Well I put it on the water last night and it is better but still a slight hesitation when it is given a full throttle. The water was too rough to run it up to high speed but it still doesn't sound right. Does anyone else have any ideas on what I should check on this thing?
 
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