Won't start, Fuel Problem

[linxlvr]

Hello all. Motor is a 9.5 Johnson, 1967 I am told, MQ-13M. Was handed as a 'no start' by a friend who was thinking of scrapping it.

Went through the 'Won't start FAQ'. It has VERY nice spark. Poured a little mix fuel down the carb, started and ran until out.

I know nothing of fuel pumps in these types of engines. (I'm an auto mechanic)
Are they rebuildable?

Also, how can one troubleshoot fuel pump vs. carb in this situation.

TY all.

--
dw

 

[iwombat]

Re: Won't start, Fuel Problem

If memory serves, the carb on this model has a drain that empties a good portion of the float bowl when its tilted.

Check this out by - pumping the bulb to fill the float bowl. Then, tilt the motor. You should see gas come out the carb overflow.

Now, run the motor with your premix in a squirt bottle until it dies. Tilt the motor. If you don't see anything out the overflow, then you've got a pump problem.

If the pump has been changed out to its more modern superceded part, it's rebuildable. The original pump is not. (again, going off of memory here).

That being said, a new fuel pump is pretty cheap for these small motors anyway. If I didn't know the history of it, I'd just get a new unit.

 

[ezeke]

Re: Won't start, Fuel Problem

The fuel pump is a lift pump, so if you have your fuel supply higher than the engine, gravity and occasionally a little pressure on the primer bulb will keep the flow up if everything else is OK. If that works, it is the fuel pump. If not move on.

The floats in the carbs are cork, sealed with shellac. Because of that, the new fuels disolve the shellac fairly quickly so that you need to replace them periodically.

The high speed jet is located immediately behind the float bowl drain, where it can be reached for a little cleanout with the tube on your gumout aerosol.

The parts catalog for the 1968 9.5 will show most of the parts. There are a few changes, but nothing spectacular.

If the fuel pump that you have is approximately 1-1/2 inch square, let me know and I can direct you to a good rebuild guide.

For the parts manuals, copy the link to your browser without the quotation marks:
"http://epc.brp.com/default.aspx?brands=ej&lang=e" BRP Parts Catalogs

 

[ezeke]

Re: Won't start, Fuel Problem

One other thing; the screen in the front of the fuel pump needs to be clean and the gasket between the fuel pump and the engine needs to be in good condition and air tight.

 

[linxlvr]

Re: Won't start, Fuel Problem

TY all for your help. Hopefully will get to try out everything tomorrow and see where we go from there.
--
dw