rebuild ideas

breefart

Cadet
Joined
Apr 26, 2011
Messages
9
Hay guy
I have a old 1977 85hp johnson javelin and its lacking power. I want to give this old beast a new lease in life.
I want to know what are the things i should do can anyone give me a list. Like carby kit, new coils, powerpack stuff like that. I have a little idea on what to do. But a list from someone on the stuff i should change and do would be great.
Thanks
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: rebuild ideas

First of all, make sure that engine has good compression. No point in putting any $ into it if the compression is low-unless you are going for a complete ovehaul. Look for compression in the 120-125 lbs range on all 4 cyls. Keep in mind that your engine is a 92 cubic inch small bore model. The 1977 115/140 engines are 99.6 cubic inch blocks.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: rebuild ideas

What evidence do you have that it needs anything done, Mate? "Lacking power" tells me nothing. How did you determine that?

Keep in mind the wrench's motto, "If it ain't broke, don't fix it."
 

breefart

Cadet
Joined
Apr 26, 2011
Messages
9
Re: rebuild ideas

Evidence would be. The take off speed is crap. Cant pull up a ski. And the motor has never been touch. And i just feel after 34 years of life it could do withh some work.
But i like your moto.
Tim
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: rebuild ideas

Must have changed the impeller?

Start with emdsapmgrs advice and get some compression readings. Let us know what you find.

You will then need to check spark on all cylinders. Replacing a coil/powerpack on a cylinder that is firing fine will do nothing for you other than lighten your wallet.

If she is not running on all cylinders, it is time to find out why.

Routine maintainence that should be performed is the water pump(roughly 3 to 5 years), gearcase oil (at least yearly, depending on use), plugs (I put fresh ones in every year, as they are cheap and I boat alot, but that is up to you), and Im sure if that carb hasnt been cleaned/rebuilt in a few years it definately couldnt hurt.

Let us know what you find.
 
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