Volvo 4.3l GXi/OSi 2008 Engine cuts out under load

greener14519

Cadet
Joined
May 4, 2013
Messages
13
This engine, in a 23.5' pontoon has several problems and I wonder if they can be related.
1) Under load, at about 3000 RPM the engine falls flat as if it ran completely out of gas. This happens for about one second and the frequency starts at about once every three to four seconds and then gets worse. If I push more throttle, the choking out gets worse and then the engine starts to backfire like an excessively lean mixture. Pulling the throttle back will cause the engine to smooth out. Immediately after the first sputter, there begins a periodic beeping sound from the drive console, the same beep that the boat makes when I first turn on the key.
I checked fuel pressure at both fittings. The schrader valve at the bottom of the primary pump reads 19 PSI and the one on the fuel rail reads 60 PSI, both maintain that pressure, even as the engine is choking out. There is even the tiniest little spike upwards as the engine coughs, probably caused by the vacuum pressure regulator.
I looked into the distributor cap (clean and dry) and checked the coil wire. All good there as far as I can tell.
2) This engine has a history of throwing the serpentine belt. Yesterday, some people were using the boat and the belt came off. They drove the boat for at least 20 minutes, not knowing that the belt came off. They did tell me that they heard the beeping sound from the console. They didn't notice the temperature gage so I don't know if it overheated, but I'm assuming it did. This afternoon I found that the power steering pump was loose and so I tightened the bolts on its brackets. This straightened up the pump, but I can see that the serpentine belt is still trying to walk off the harmonic balancer. So far, it hasn't come off, but it squeals like a stuck pig. The balancer has a little bit of wobble to it, but it doesn't seem enough to make the belt walk off.
3) There is a rumbling/rattling while in forward and reverse, and it gets worse as the steering is turned. I'm assuming this is either a u-joint or a gimbal bearing.
4) The drive is hard to steer to the left, but easy to steer right and the left turns get noticeably harder at higher speeds. I'm guessing that would be a bad steering cable.
Any advise or suggestions on where to look next?
Thank you!
 

Bondo

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Apr 17, 2002
Messages
71,095
Re: Volvo 4.3l GXi/OSi 2008 Engine cuts out under load

Ayuh,..... My Guesses are,....

#1,... Crud/ Water in the fuel filter, or a restriction 'tween the tank, 'n pump,... or at the 2ndary pump,...

#2,... Atleast 1 of the pulleys is out of alignment, or an accessory has a failin' bearing,... water pump, idler, ??

#3,... u-joints or gimbal bearin',...

#4,... Try a Different prop,...
 
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greener14519

Cadet
Joined
May 4, 2013
Messages
13
Re: Volvo 4.3l GXi/OSi 2008 Engine cuts out under load

Thank you Bondo for the reply. As I mentioned in my original post, I'm thinking it's not likely a fuel supply problem. The pressure at the fuel rail stays a steady 60 PSI even as the engine falls flat. I failed to mention that the first thing I did yesterday was replace the fuel filter. It was after that didn't fix the problem that I put the gage on her.
As for the belt issue, all of the pulleys seem to be in alignment. All bearings are good. The tensioner was replaced on Friday by someone else and I confirmed proper operation and alignment. What's realy odd is that the belt is walking off the crankshaft pulley on the leading edge. This is fed from the water pump pulley. The water pump spins straight and true. I'm starting to think that there is a problem with the crankshaft or harmonic balancer. I have seen an engine run with a broken crankshaft, near the timing chain. However, with my hands I cannot move the crank pulley at all.
Last question: why would the wrong prop cause a binding steering, even at low speeds? It seems I have a lot to learn here.
 
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