1983 Johnson Seahorse 4hp overhaul/ service

[felix_no1]

Hi all,

I have just acquired a Johnson 4hp Seahorse longshaft outboard. I dont have the model and serial number to hand but have checked it and it relates to the above year.

Basically the motor is runnong ok, albeit a bit rough but as i have no history on it i want to do a bit of a service/overhaul so things dont go wrong.

Have any of you got any recommendations on what i should be doing.

Cheers

Felix

 

[Vic.S]

Re: 1983 Johnson Seahorse 4hp overhaul/ service

Check compressions ( give away again if low or very different!)
Renew plugs (L86C , gapped 0.30")
Check sparks
Inspect coil and clean reset points perhaps (But those require flywheel to be removed so only if sparks not good)
Ditch all old fuel and flush out tank. New fuel at 50:1 using TCW3 oil
Clean fuel filter on pump if a remote tank model
Strip and clean carb
Renew water pump impeller.
Drain and renew gear oil. If milky looking or actual water present renew seals.
Grease all greasing points and generally oil and grease external moving parts

See also http://forums.iboats.com/showthread.php?t=158086

 

[JB]

Re: 1983 Johnson Seahorse 4hp overhaul/ service

"Low" compression would be less than 50psi. Bad compression would be if the two cylinders are not within 15% of each other.

If gearcase oil is milky or there is water in there first renew the plug gaskets, as failure to replace on every change is the most common cause. If that doesn't help, renew seals.

Everything else that Vic says.

 

[felix_no1]

Re: 1983 Johnson Seahorse 4hp overhaul/ service

Thanks folks.

How do i check the compression?

cheers,

Felix