It's ALIVE!! 1983 Johnson 9.9 HP - should I do anything to clean up the insides?

[JCCinOhio]

I recently got a J10ELCTC that hadn't been run for 3+ years.. and no idea on history before that. Got the kits for the fuel pump and carb and installed them as well as a few other odds/ends. Started up pretty easily after that. Has right at about 100psi in both cylinders. Took it for a float test and it ran ok. This is my first boat.... so although I'm an ok mechanic, I don't know about boat motors..

Is there anything I should run through the motor to try to clean it up, or is that stuff just a gimmick? I've seen reference to de-carbing. Or should I just run a tank or so of fuel/oil thru it to burn off anything that might be in there?

Thanks!

 

[racerone]

A new water pump impeller is a MUST DO item.

 

[Vic.S]

A new water pump impeller is a MUST DO item.

beat me to that by a few minutes

Change gear oil too... If there are signs of water ingress check it again after a short period of use and if signs of water getting in renew the seals

Otherwise beware of fixing what is not broken

 

[JCCinOhio]

Sorry, should have added that I did change the impeller and the lower unit oil.. I was thinking more engine performance, but understand how that relates.

 

[iggyw1]

Seafoam works great to clean up an engine. It is a fuel additive. Give it a little heavier dose to start out on the first tank of fuel, then it is recommended to use it every tankful at 1/2 to 1 oz. per gallon. I use it religiously but still running into a problem with my idle on my motor, but my engine is very clean inside!!