'88 Penta AQ290A (GMC) 5.7L water pump impeller trouble

My lower unit was not (peeing) so I checked impeller. It is off center and not pulling water, not sure if water pump can be rebuilt, or needs replaced. I ran motor maybe 20 secs and turned off. Was going to remove water pump to check. When I removed hoses, I also noticed a small drip from front of head gasket. Motor will crank, and zero water in oil. No clue what's going on. Thanks for any advice pic of impeller attached.

Re: '88 Penta AQ290A (GMC) 5.7L water pump impeller trouble

Sorry pic file was too large...this should work now..

Re: '88 Penta AQ290A (GMC) 5.7L water pump impeller trouble

Welcome to iboats.

Charlie R said:

My lower unit was not (peeing) so I checked impeller. It is off center and not pulling water, not sure if water pump can be rebuilt, or needs replaced.

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Your "off center" impeller is a huge problem..... actually its exactly as it should be. The impeller is supposed to be off center. The bending and squishing of the impeller is what makes the impeller pump water. Not sure what you mean about the outdrive "peeing". The majority of water exiting the outdrive should be coming out of the exhaust port. When you were running your engine, I assume you were running it on muff's with the garden hose turned on, right? When is the last time the impeller has been replaced BTW?

Another item to check is number 25 in the picture in this link. More specifically, where the inlet hose connects to part #25. The;http://www.volvopentastore.com/Inte...*****.278377226--store_id.366--view_id.780525

The neck on that part will corrode away (especially in salt water), and allow the impeller to suck air rather than water. Take the hose off that part, and take a good look at it.

Charlie R said:

I also noticed a small drip from front of head gasket. Motor will crank, and zero water in oil.

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I am assuming this is a water drip, not oil, right? Are you sure the drip is not originating around the intake gasket and following the gap between the head and block down? If you suspect a leaking gasket, now is the time to replace it before you have water in the oil, or hydro-lock the engine, or get stranded.

Re: '88 Penta AQ290A (GMC) 5.7L water pump impeller trouble

Thanks for the reply that makes sense.... When water was not coming out, yes with muffs on, I got concerned....replaced impeller, ran it again and still no water. I removed the inlet hose at the hydraulic fluid cooler, and stuck the garden hose directly into it. Got plenty then. So possibly the fitting you explained is the culprit. I see no way to get to it though without dropping the drive unit. Am I correct?

Re: '88 Penta AQ290A (GMC) 5.7L water pump impeller trouble

Charlie R said:

Thanks for the reply that makes sense.... When water was not coming out, yes with muffs on, I got concerned....replaced impeller, ran it again and still no water. I removed the inlet hose at the hydraulic fluid cooler, and stuck the garden hose directly into it. Got plenty then. So possibly the fitting you explained is the culprit. I see no way to get to it though without dropping the drive unit. Am I correct?

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To tell you the truth, I've never had my hands on a 290. I deal with a 280 which is a similar drive. I could probably get that neck off my 280 with the drive hard over to one side and some swiveling sockets on a 1/4 drive ratchet. Hopefully one of the guru's will chime in and give you a yes/no. Worst case, I believe the upper gear box can be separated from the lower so you won't have to pull the whole drive. At that point, you should be able to gain access to the neck. It would also give you a great opportunity to replace the drive bellows if they haven't been replaced recently, and check out the U-joints.