sucked up some sand in my powerquest. 454 merc. shut it down took it in had the marina flushed it out. install new t-stat. had new impeller and housing installed.

went to lake, boat slowly kept climbing in temp. went to 215 shut it down let it cool. went to dock started it back up ant temp just slowly climbs.

my thinking is there is still sand in the system even thought marina said they flushed the hole system .

my question is could i remove the t-stat to get higher water flow and see if that flushes the system better/ any ideas

Sure you can, but I don't think that will solve the problem unless the marina put in a high T-stat. I think I'd slap some earmuffs on it (in the driveway) and see the water flow out to see if there are any restrictions.

bravo? pull hose off in of sea pump and stick garden hose in and blow it back out thru the transom. skinny spot at fitting in transom coulda caught a shell or rock...you wanna get really thorough, pull drive, pull both hoses off and put a brush through fitting. it packs up with stuff over time.

I had exactly the same problem and did all that you did plus pulling hoses and back flushing but none of it helped. I ended up pulling the water pump off the block and shot high pressure water into the hole. A ton of sand came out of the block. No problems since.

Pull drain plugs in botton side of block. Water should come out. If not block still has sand in it. Has water pump inpleller been replaced? If so, were there parts missing and they collected them all. Pull hose right before cooler and see if any parts are stuck there.

My out drive has the water pick ups in the front so my old muffs wont work. yes has new impeller and there was no broken off pieces. Also new impeller housing. I have pulled the hoses and back blew it best i could. I also pull t-stat backed it in lake and let it run for a bit i could literally catch sand in my hand coming out of the header. they did a nice job of flushing it out drove it for about an hour and it didn't even move the gauge. im putting a new t-stat in it today and hope it is all good to go know

Sounds like the Marina had you scheduled for an Impeller or Motor Replacement! I hate paying anybody to touch my $hit for that reason.

i have used cut-down plastic barrel to fit under outdrive, put fitting in bottom to take garden hose. the hose fitting helps fill and drain, only way to get enough water to flush cooling system.

new t-stat and running perfect now. running about 180-182 all day long when it was 100 degrees out . problem fixed. Boat is forsale also looking for something smaller