9.5 Died Slowly

[brianwrites]

On my way back to the boat ramp and my 1965 9.9 Johnson Seahorse MQ-11 died. It went from full RPMs to 0 in about 10 seconds. It sounded like it was slowly running out of gas, but there was plenty and pressure in the fuel line squeeze bulb. Any idea where I should start diagnosing the problem? I've got all the manuals and part catalogues. Thanks for any and all starting advice.

Brian

 

[jbjennings]

Re: 9.5 Died Slowly

Running out of fuel usually causes a real quick stop vs. a slow one. I would make darn sure it didn't overheat and is staying cool. If so, I'd try to run it again and if the problem happens, try seeing what happens when you take the cowl off. Those motors often get exhaust leaks which will starve the engine for oxygen.
My suspicion would be an overheat or exhaust leak.
JMO,
JBJ

 

[RSchendel]

Re: 9.5 Died Slowly

I had a similar incident on my 1957 Evinrude Lightwin (3HP). The powerhead was very hot when the motor slowed down and shut off. Turned out to be an impeller that went bad. The motor was overheated. Lucky for me, everything worked fine after I replace the impeller. All 6 points of the impeller were broken. I suspect they broke over time and I did not notice the gradual decrease in water outlet flow.

On the plus side, as I was rowing back to the boat launch, my father caught a Muskie while trolling under human power.

 

[brianwrites]

Re: 9.5 Died Slowly

I cranked her up today and she started right up. I shut her down immediately. How do i tell if she overheated. Run her in the barrel and see if she dies again? Any ideas. Thanks for your help.

 

[jbjennings]

Re: 9.5 Died Slowly

Does it have water flowing out of the tattle-tail?
Run it for a short time, feeling of the cylinder heads as it warms up. If it gets past the point that you can hold your hand on it for 3 seconds without it burning you, it's getting too hot. You can also get an infrared digital thermometer at harbor freight tools for about $20 or less. It shouldn't get over 140 degrees.
Good luck,
JBJ

 

[brianwrites]

Re: 9.5 Died Slowly

Tattle Tail. Is that the port just above the bottom of the cowl? If so, yes.

I ran it in a barrel and found the following.

1. Lots of smoke.
2. Gas was leaking out of carburetor.
3. With the cowl on, she wanted to die. As soon as I took the cowl off, she would come back to life and increaes the RPMs.
4. After the run, there was black gook floating in the wate inside the barrel.

Does this sound like carb overhaul? Complere overhaul, improper fuel mixture?

Thanks again for your help.

B

 

[jbjennings]

Re: 9.5 Died Slowly

Running a 9.5 or most any other motor in a trashcan without a fan to blow the exhaust away will cause problems, but especially with a 9.5.

You need to rebuild your carb. and possibly get a new float, and hope your exhaust seals are o.k. If it won't run on the boat at the lake without the cowl off, you probably have an exhaust leak. I'd just run it without the cowl in that case. You don't want to pay to have the exhaust seals replaced, and don't want to try it yourself without a manual, it's not easy.

Black gunk in the barrel is perfectly normal. So is the smoke.

I seriously doubt you need a complete overhaul. That motor wouldn't be worth doing an overhaul on anyway.
JMO,
JBJ