1969 Johnson 9.5 - sudden loss of power

[Kernewek]

I have a 1969 Johnson 9.5 on my 14' aluminum, normally this motor runs great, but last time I had it out after running for about 2 hours, mostly trolling but also at full speed it stalled on me, took me a few tries to get it started again then it would only run a little above idle speed even with the throttle wide open.
I thought that it may be a fuel problem but I had a full tank of properly mixed fresh gas.I plan to check the ignition system -coils, points and condensers,(plugs were new this year) and replace as necessary
Any other suggestions of what to look for would be greatly appreciated

Thanks in advance

Mike

 

[kfa4303]

Re: 1969 Johnson 9.5 - sudden loss of power

HI Kernewek. Welcome to iboats. Usually, a sudden loss of power like you described is an electrical/ignition issue. You probably lost a cylinder. I would pull the fly wheel, inspect the coils, clean and regap the points to .020". Make sure the spark plug wires haven't wiggled loose of the coil posts and aren't corroded or scorched. It never hurts to clean the carb too. You can get all the parts you need right here at iboats.A tune up kit with points and condensers is about $20 and a carb kit is about the same. Here are some handy links.

http://www.duckworksmagazine.com/06/columns/max/index6.htm
http://forums.iboats.com/showthread.php?t=167352

 

[Rick.]

Re: 1969 Johnson 9.5 - sudden loss of power

Certainly agree with above but I would start with a spark gap tester that way you will know which is not firing if that is the problem (and I think it likely is). Spark should jump 3/8 of an inch and be blue/white and snappy. Best of luck. Rick.

 

[cajuncook1]

Re: 1969 Johnson 9.5 - sudden loss of power

Rick, has a very good point. Before you start tearing everything up and buying kits. Check both cylinder for spark with a spark checker. Also check your spark plugs, even though they are new they could be fouled up with oil or carbon from a lot of trolling at low speeds. If that is the case, then go with a hotter plug like Champion J6C. Spark can't jump through junk and carbon build up. For the time being, clean the spark plugs off if they have junk or caked with carbon and see if it makes a difference.

As always, make sure your engine is not overheating and cooling properly. Should have a good thick spray of water coming out of the water outlet/exhaust relief port.

Check your fuel pump screen to make sure it is not gummed up with trash that could affect fuel delivery. If if is running at half power then pump the bulb, if it increases speed,them you may have a bad fuel pump.

All these checks, don't cost you dime and you can rule out the simple free stuff and then move on to more detail assessment like removing the flywheel and checking out your points, condensers and coils. If that is not the case then move onto the carburetor. Unfortunately, Sierra does not have a carburetor kit for your motor. It is only a OMC/BRP item.

Here is the part number for the carburetor kit. OMC PART # 382048


I'm not telling you disregard, what the other fine gentlemen are stating, I'm stating that you check the simple and free stuff first. Some times you might be surprised!!

 

[Kernewek]

Re: 1969 Johnson 9.5 - sudden loss of power

Thanks for all the good advice gents, I guess I know what I will be doing this weekend