Overheating

[DaveB 5]

I am leaning to the circulation pump thought just because may heater isn't blowing warm

[superdtf 68]

I am leaning to the circulation pump thought just because may heater isn't blowing warm

That's astute. If you do change it out, take it apart and look at the vanes. I'm curious if they're corroded. I'm suspicious that many of us operate in waterways that might be more corrosive than we imagine.

[DaveB 5]

I'm pretty much down to a matter of elimination now until I go broke

[Pildo 6]

I was having same problem as Dave B. I removed impeller and compared it to last years. It was the same size. Removed t stat housing and checked all hoses for blockage. All were clear. Drilled a 3/16 hole in t stat. Ran engine for a half hour on hose and it held at 175. Water test this weekend for true results.

[superdtf 68]

I was having same problem as Dave B. I removed impeller and compared it to last years. It was the same size. Removed t stat housing and checked all hoses for blockage. All were clear. Drilled a 3/16 hole in t stat. Ran engine for a half hour on hose and it held at 175. Water test this weekend for true results.

I think you have a failing t-stat on your hands. Super cheap part to replace.

[Pildo 6]

New t stat

[DaveB 5]

Problem finally solved. After changing impeller,thermostat,circulating pump and serp. belt, I still had the overheating problem at idle, really didn`t want to pull the raw water pump for the third time but ran out of options. So I pulled the pump again and sure enough h20king you were bang on the back plate was scored pretty bad and also slightly warped, so I sanded it down almost smooth and slightly dressed the impeller side of the pump and put it back together started it up and it held just under 175. I will order a new backing plate ( upgraded ) and change the plate next time. ( I`m pretty good at taking the pump off now can do it in about 10 mins). Thanks h20king for your diagnosis and everyone else that gave their input

[h20king 794]

You are very welcome now go have some fun

[superdtf 68]

You are very welcome now go have some fun

Nice H. I really wasn't thinking that was the one. You rule.

[Pildo 6]

Is the back plate suppose to be smooth where the impeller rides on it?.

[Pildo 6]

Is the back plate suppose to be smooth where the impeller rides on it?.

[DaveB 5]

I'm not sure, I sanded it down but left a bit of a groove where you can see where the impeller rides. Being brass it's going to wear pretty quick .

[Pildo 6]

When I hook the hose up to the boat in the driveway water gets past the impeller before I start the engine. Is this normal?

[DaveB 5]

I think that is fine at least you know you have water there, I'm sure there will be some work its way around the impeller

[Chyannw 0]

I have this exact same overheating problem and done everything possible to fix it. New Impeller and housing, new pump kit, changed all oils, new thermostat and my gauge still says overheating. Is it possible for the thermostat gauge to go bad?

[duramat 462]

I have this exact same overheating problem and done everything possible to fix it. New Impeller and housing, new pump kit, changed all oils, new thermostat and my gauge still says overheating. Is it possible for the thermostat gauge to go bad?

Checked tranny filter?

[Chyannw 0]

Checked tranny filter?

Is it internal or external? I have not seen an external tranny filter.

[superdtf 68]

It's an external "shell and tube" heat exchanger to cool the transmission fluid. It's directly above the transmission and you can see that water goes in and then out through the ends, and transmission fluid flows through small lines on the side. Pull the water hoses off and give it a look.

[DaveB 5]

Does your temp stay high or drop with increased rpm