Volvo Engine Vibration Issues

[Rob4044]

I bought a 2006 Crownline LS early this summer that has a 5.0 Volvo in it. A few weeks ago I started noticing that when I started the boat the engine sounded rough and vibrated. I looked at the engine and notice that the steering mechanism behind the motor was moving rapidly back and forth causing the movement that I felt. After about 20 seconds it usually comes out of it. If I shut the engine off and restart then it starts just fine. It's always on the initial start. Yesterday, I noticed a slight whine in the engine and also noticed my oil pressure was down to almost nothing when idling. When cruising the oil pressure seemed normal. Also yesterday, when I initially started cruising the engine cut out momentarily twice. I didn't have to restart though. It's like it just momentarily lost power. I've been noticing a gas slick in the water when I pull the plug lately as well. I'm not sure if it is related but wanted to throw that out there. My initial thought is that my oil pump may be going bad. I have a short video of what the engine is doing but wasn't able to upload it. I could email it to someone if it was helpful . Any thoughts would be appreciated!

 

[alldodge]

Its a 5.0 what, carb, efi, mpi GI, GXI?
Also what kind of maintenance have you done to the boat this year?

 

[Rob4044]

EFI, GXI. No maintenance has been done this year. I just bought the boat in May and have put about 10 hours on it.

 

[Rob4044]

Here's a link to the video of the engine running. Notice the steering rod moving side to side (on it's own) and then stopping. If I shut off and restart it doesn't happen. https://youtu.be/iiX9hZj7cww

 

[alldodge]

So the rocking stops on its own given a short bit of time?
Will it stop if you turn the wheel?
Check the power steering reservoir for correct fluid level. Check to see if the steering cable nut which fastens the cable to the ram.

Need to change the fuel filter and when its removed, pour the contents into a baggie and see if there is anything besides clean gas. Refill the new filter with gas, apply a small amount of motor oil on the seal and then install.

With the motor running rich, need to find out why. Remove the flame arrestor and clean it. Down the throat of the throttle body (TB) there is a piece of foam rubber, this is the IAC muffler. Gently remove it and clean with soap and water.

If this doesn't fix the issues, were going to need to find out what the fuel pressure is and then if it has any codes showing in the ECM

 

[Rob4044]

Yes, the rocking eventually stops on its own after 15-20 seconds. Not sure if it stops if I turn the wheel. I'll have to check on that. It's strange why it only happens when I initially start it and then if I shut off and restart it's perfectly fine. I'm concerned about my oil pressure as well as it was only running at about 8 psi when idling back into the marina. That's seems very low to me. I might have a couple of things going on. Not sure why it cut out on my twice yesterday while initially getting up to cruising speed.

I sure appreciate your time and help on this. I won't be back out to the river until next weekend so won't be able to address anything until then.

 

[alldodge]

The low pressure could be a problem but could also be a gauge or sender issue. Only way to know for sure is with a mechanical gauge. Can remove the sender and install a mechanical gauge, or install a tee so they can be compared.