Engine Overheating at Higher Speed/RPM, Helpful Solution

[WayneP]

Good work. Great feeling when you find it. Looks exactly like the pieces of impellor that were in my one way valve.
Yes, I see from some diagrams that there are two valves. My engine only has that one vertical blue yellow valve but same problem,
"Much crud on input side = random flow on output side".
I knew that one day I would come up with E=MC squared. But for boat engines! The difficulty we both encountered was the random flow random cooling issue.

 

[Bill Curtis]

Interesting I have heard people say they have found impeller pieces in there. Thanks man see you soon

Yeah, mine has tubes in it, lots of them

 

[Bill Curtis]

Problem solved folks! I just want to thank everyone for your replies. I think I took a little nugget from everyone to solve this :

Before I dropped this new Hardin pump in I thought I’d take one more crack at the the ps cooler in the back. I was able to get hoses off to backflush. When I did very little water came out. Hello, a clog someplace !! There is a check valve in this side too. I knew there was one on the other side but I did not see this one. I was able to get to it from under the engine. Follow the outlet hose from pump and it goes back to an elbow fitting then up to this check valve. I was able to remove that hose and BINGO! Full of bunch of impeller pieces. It was really packed in there. Had to take some long handle needle nose pliers to grab what I could. Then was able to back flush!

Put it all back together and bam! All fixed. Took her out ran full throttle for solid 20 min. Temp stayed right at 165 didn’t budge and my water psi was 12-13 !!! Much better than the 3 it was getting before.

My current pump is still good and I hope to return the Hardin.

Wow what an adventure. But now I know what to look for. It’s pretty easy to fix. Lol see pic of the culprit that eluded me for a longtime in pic. And thank you all so much for all your comments

Awesome work. Glad you found it and had the perseverance to keep looking.

 

[km1125]

Glad you found the issue!!

In the future, if you (or anyone) is having trouble backflushing, you might want to try a shop vac instead. Disco the hoses then use the vac to suck "backwards' though the system. If you have larger hoses, you can also extend the shop vac hose by taping a length of smaller flexible bilge pump hose that will slide inside the water hose.

 

[Scott215]

You would thinks with technology they would make an impeller that is no rubber but some synthetic compound that would last for 10 12 years. Just a thought