Sporadic Alarm on take off 326 AFT

[bud37]

Yes we are looking for the correct belt tension that would drive the pumps, alt etc.Check/ compare the belt tension port side against the known good one Stbd.......finger twist the belt 90 degrees from the way it is and compare the tension it takes to do it....is there any belt noise on startup ? This might not be anything but good to cross off the list considering it has been worked on.

Google serpentine belt tension check...lots of u tube stuff, might help visuallizing.

[Marty]

One last point that came to mind was that when they dropped the boat in the water the port engine overheated because there was an airlock in the seawater intake. Pump had to be primed and then ran fine but I’m wondering if the impellor was fried because of it?

[bud37]

Absolutely......if it ran for a just a few minutes you can destroy or a the very least damage its ability to pump maximum .....next job change out impeller.

Was this before you brought the boat home ?

[Marty]

Ok at the risk of sounding stupid here change out the seawater intake impellor? VS water pump?

Sorry for the rookie mechanical questions. I’m ok with a wrench as long as I have good instructions but more experienced with a hammer and saw.

Thank you for your assistance thus far.

[waybomb]

Sea water pump.
Make sure you have all the pieces from the old impeller. If not, have to start searching downstream because the pieces can restrict flow.

[Marty]

That made me chuckle. Got it and thanks guys!!

[tomschauer]

Marty, as Fred says, first check the seawater pump impeller. If you follow the hose to from the through hull it would be the first point it attaches to on the engine. Looking at the front of the engine it should be on your lower right side I believe on the 5.7 liter. If any r pieces or missing, its most likely your problem. Either way, replace the impeller, O rings and wear plate (make sure you get the in and out correct when you reassemble) and you should be good there for a couple years. If you find no issue and still have a problem AND your motors are raw water cooled (no heat exchanger with anti freeze) you may want to look at the water pump mounted front and center of the engine as I mentioned before.

Not trying to insult your intelligence, just not sure of your mechanical knowledge.

[tomschauer]

Sorry, lower left side of the engine for the seawater pump!!!!!

[Marty]

Yeah no worries...no offense taken at all as my mechanical knowledge is limited and I appreciate the support.

Am I correct in identifying the replacement impeller kit for a 5.7L mercruiser 350 MPI as

47-8M0104229

Thanks,

[bud37]

Marty, if you have the plastic pump housing then you should get the kit with the housing as well, as it would be good to start with all new an that side. I would remove the entire pump from the engine and do the work on the table, much easier.......honestly if I were you I would hire someone to do that side and watch how its done for the first time, no harm in that, a bit tricky.
That way the belt will get tightened correctly and maybe he notices something while doing the work.Considering your problem with that side I think it may be a win win for you.