Powerhead seized while idling 2.5 HP

[Aquatical]

A couple of weeks ago I bought a 1988 2.5 HP Johnson as a kicker motor- model J3RCCM - apparently it was lightly used, and only in fresh water. Started fine- only thing I did was change the spark plugs which were the originals! Took it out yesterday and ran it at WOT for about 45 mins, ran great. Using 50:1 mix. Then started lowering the throttle to better adjust the low speed valve - when it when suddenly when "clunk" and died. The rewind starter cord was impossible to pull. Took it home, the flywheel could not be turned by hand. Removed the lower unit and that was fine. Then started to take off the flywheel nut with a rachet and with a bit of force, it unfroze! Now it turns fine, and I can hear no funny sounds at all inside, so I am clueless as to whether I have a major or minor problem.

 

[Xcusme]

Re: Powerhead seized while idling 2.5 HP

Welcome to iboats!

Well, first off, you've found out from the get go .. what happens when you run a motor with little or no report from the water cooling system. The motor was over heated and it froze.

Replace the cooling impeller first and see what needs you attention.

 

[Rick.]

Re: Powerhead seized while idling 2.5 HP

Sure sounds like an overheat to me as well. Replace your impeller before trying it again. Best of luck. Rick.

 

[Aquatical]

Re: Powerhead seized while idling 2.5 HP

Thanks, Commander. Glad to have joined, I love this fourm BTW. I will check out the cooling system. Perhaps the root cause are worn water pump impellers that only function adequately at higher RPM, but at low RPM, cannot circulate enough water, or else a partial blockage is preventing adequate water flow at lower RPM?