115 Johnson 1990 Fuel problems??

[DeeDubb]

1990 115 Johnson Outboard. Ran fantastic when I shut if off last time we used it. Did not use last year (2009). Started this Spring and would not stay running. Would run rough at idle, but not allow me to increase rpm as engine would bog down & die. Dealer recommended carb rebuild. We installed the carb kits (Floats & seats), O-Rings on Fuel bowl ends. Will start fine, begins to run rough, and dies. Throttle controls will kill engine when advanced. I can mannually run up the engine at the carburators and it runs fine, strong and smooth.

Now another fellow tells me the compression is too low. I would like to make an informed decison to repair or sell. But everyone has there hand out for cash to help. This is a twenty-year old motor and I want to make an informed decision to make it run or junk/sell it.

Question: Should I invenst in a professional to rebuild the carbs and set up the fuel system. Should that solve the problem?

Thanks, DeeDubb

 

[Captain Jeff]

Re: 115 Johnson 1990 Fuel problems??

What is the compression on each cylinder? It sounds like you may have a timing issue since it runs fine when you are bypassing the throttle controls.

 

[DeeDubb]

Re: 115 Johnson 1990 Fuel problems??

This fellow said it was 50 - 60. Never really got warm. I know of no instance that would cause that except not winterizing it when we stopped usingit. Ran fin then.

 

[emdsapmgr]

Re: 115 Johnson 1990 Fuel problems??

The compression on that engine when new was probably around 90 to 95. Your current readings are very low. You will be unhappy with any performance from the engine as it is. You can try some Bombardier Engine Tuner, but it is unlikely that the compression will recover 30 to 40 lbs. You may need an overhaul.

 

[DeeDubb]

Re: 115 Johnson 1990 Fuel problems??

My main question is: Could, not winterizing the engine, let it sit for a year, cause the compression to drop that far? Again, all was well when I last used it.

Thanks!

 

[ezeke]

Re: 115 Johnson 1990 Fuel problems??

If the engine was not winterized, the rings could rust and stick, which would result in low readings. Also, if the engine was stored improperly (not in running position) it could not drain properly and may have suffered damage from freezing and/or rust.

It would not take very long to pull the cylinder heads and investigate.

It's unusual for all of the cylinders to read low. I would try another gauge before anything else.

 

[Captain Jeff]

Re: 115 Johnson 1990 Fuel problems??

Rust and corrosion can form on the cylinder walls and piston rings and cause loss of compression if the engine was not fogged. As far as how quickly this happens depends somewhat on storage conditions, humidity, etc. I have not personally experienced it so I cannot say for sure. Like emdsapmgr said, it could be worth squirting some engine tuner or seafoam in each cylinder, turn the engine over to distribute the seafoam and let it sit a while to clean deposits from these surfaces.

 

[emdsapmgr]

Re: 115 Johnson 1990 Fuel problems??

You might check one other thing. If you have ingested water into the engine during the last use. That water may have rusted the cyl walls, causing your low compression. It is possible that you may have water in the fuel. I'd do a fuel sample from your tank and see what it shows. Also, I have seen the remote oil tanks with water in the bottom of them. Check the bottom of that tank for water also.