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Poppet valve or tstat?

T

TritonFisher

Regular Contributor
Dug more into my 95 merc 60 two stroke today. Boat ran fine and out the tell tale on muffs, but in a barrel it needed higher rpm’s to get flow then alarmed after I throttled down (and stream stopped).
-Impeller and housing looks fine. Key is all set in right spot.
-Hose pressure up the tube flowed through the system with no blockages or issue.

I was familiar with the poppet and t stats from my Honda outboard, but not sure about this setup. Any way to rule one out over the other?
 
Don't make any decisions on barrel tests. Get out on the water and do your testing. The T stat controls cooling below 2500 RPM on my Mercs. Over 2500 additional flow is needed so the poppet opens and essentially bypasses the t stat as the incoming water is cooler than the Tstat opening temp, but the poppet is larger in diameter and made to handle the increased flow at higher RPMs. So it's not rocket science. If you are in an RPM range and get the horn, change to the other range and see if it quits. If so, that valve is your OT source.

I bought a 2 year old 2002 90 Merc with rig. First time out I putted out the no wake zone, taking 5 min. or so to get out. No horn. Clear the buoys and hit the throttle, get up on plane running at a good clip and all of a sudden I get the horn. Wondering what's this, I chop the trottle to a low RPM and the horn quits. Repeat the process and get the same results.

Get home and investigate..... the Poppet was stuck shut.
 
Tested the tstat and opened right at 143–poppet was fine as well.

I was right above the inlet in the bucket - definitely not enough pressure.

Thanks for the help—will get it on the water Sunday. Fingers crossed!
 
An impeller can look fine, but that has nothing to do with how well it moves water. If it hasn't been changed in years, spend the money instead of wasting time- it was already disassembled, why not just replace it?
 
Took the trial run today. Pumped way more water than I was anticipating. So far it’s a good running motor—now to figure out fuel usage.
 
Took the trial run today. Pumped way more water than I was anticipating. So far it’s a good running motor—now to figure out fuel usage
 
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