1985 Joshnon 15 Fuel Issue?

Tinny Fleet · Apr 11, 2017

This is a new motor to the board, not covered by any previous post.

I have a 15 hp Johnson 1985 version. Will not start unless I dump gas in the carburetor. And then runs only long enough to burn the gas up. It will respond to adjustments in throttle.

Checked the fuel pump: it seems to be working although somewhat weakly - still pumps gas.

I have tried to seafoam the carb in place, by dumping seafoam into the carb to try to clean it out. no result.

The linkage appears to be all intact and functioning.

What is my next step? Replace fuel pump? Rebuild carb?

Thanks in advance

Whit

timsmcm · Apr 11, 2017

Is this a new motor to you? Do you know it's past? If it is new to you and you don't know it's past, I would rebuild the carb 100% complete (in a carb dip to make sure all passages are clean), rebuild the fuel pump, check to make sure all all fuel tank parts and lines work and unobstructed, new complete water pump assembly, new lower end oil and a lower end pressure check to see if any leaks. But that is just me, don't want to paddle across a lake. I have an 85 evinrude 15 hp. My favorite motor out of all the motors I own. Treat it right and it will last forever. Also you will need a new thermostat.

Pappy · Apr 11, 2017

Tim has given you the best advice. Do all of what he suggested and you will have a super engine.
There is a ton of info in this segment on these engines. Read through them. Pretty much what you are seeing has been covered numerous times.
Only thing I can add is that you really need to buy OEM kits for the carb at the very least. That is the only complete kit out there. Same for the fuel pump and impeller or complete water pump. They fit and they work.

timsmcm · Apr 11, 2017

Pappy is 100% correct again. Use oem parts. They are not much more but there is better quality and fit. I only suggest full water pump kit because there will probably be some pitting and corrosion and that will keep you in the clear. Use anti-seize on bolts to keep galvanic corrosion lock to a minimum.