Johnson 88 spl motor issues Help Please!!!

[laniertoon08]

Hello, i need Help with my Johnson 88, I have 1991 24'toon with same year 88spl out board, I bought the boat and it hadnt run for a few years, new plugs, new gas, seafoam, etc, new prop, the old was was chewed and had big chunks missing. Runs good, idles good but when i get past 4200rpm it develops a vibration and and sounds like its workin harder but outputting less. Could this be a prop size issue , or a pitch issue causing the prop to cavitate past 4.2k rpm?

 

[ezmobee]

Re: Johnson 88 spl motor issues Help Please!!!

It could possibly be a spun prop

 

[laniertoon08]

Re: Johnson 88 spl motor issues Help Please!!!

Thanks for the advice, although I can't get the prop out of the water
To check, the prop is fairly new and feels pretty solid.
I checked the plugs and the top righthand plug was fouled
Replaced w/ champ 82L all Around. Probably need a carb rebuild
As the bottom carb is leaking a little.. Lots to do, any pointers?

 

[DargelJohn]

Re: Johnson 88 spl motor issues Help Please!!!

Start with the basics: Compression check, spark test, check your fuel lines. Has the boat run correctly since you have owned? Is the new prop the same pitch and diameter as the old one?

When it acts up at 4200 RPM's, try pumping the primer bulb.

 

[wilde1j]

Re: Johnson 88 spl motor issues Help Please!!!

Prop slipping:
1. Mark inner and outer hubs with indelible marker
2. Run boat to planning speed
3. Compare marks ? if they?ve moved relative to each other, hub is slipping
4. Remove prop
5. Take it to a propeller shop and have it rehubbed