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1966 33 HP Johnson Outboard Motor Problem

  • Thread starter Richard A. Reynolds
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Richard A. Reynolds

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" I have a 1966 33HP Johnson o

" I have a 1966 33HP Johnson outboard. It starts great, goes full blast for 5-10 minutes then slow to less than half speed.

I have had the following maintenance done.

New impeller and water pump
New points, plugs, condensers and coils
Rebuilt fuel pump.
New gas can.

Nothing seems to help. It will run all day at 6 to 7 MPH but not any faster when it gets hot.. HELP!!!! "
 
"Richard.... You didn't me

"Richard.... You didn't mention if you've tried pumping the fuel primer bulb when this problem takes place... and what happens should you do this.

You say that the engine doesn't run right when it's hot... which could mean overheating or simply that it has reached normal operating temperture. Does it overheat still?

Also, what do the s/plugs look like after this happens? Do they look alike? what color are they? do you see anything on the plugs that resembles tiny beads? If you shake a plug into your hand, is any water obvious?

What is the compression on both cylinders? Does the spark jump a 1/4"gap at cranking speed with the s/plugs out?

Joe
"
 
"Richard... I neglected to men

"Richard... I neglected to mention the make and type of s/plug that you should be using in that engine. Normally it would use J4J Champion s/plugs, but due to the age of the engine and the drop in the quality of fuel, I would strongly suggest that you use Champion J6C s/plugs. This plug is one stage hotter (less fouling) and has a copper electrode which last longer.Note.. do not use a hotter s/plug as it will cause piston damage. What make and type s/plug have you been using?

Joe
"
 
" Hi Joe.

Before I had my f


" Hi Joe.

Before I had my fuel pump rebuilt, pumping the fuel primer bulb resulted in more power. After the rebuild no difference was noted by pumping.

My motor compression test showed 115 in both cylinders.

My plugs are Champion remove.

I will check the plugs on my next run.

My mechanic has suggested me to remove my motor hood to see if there is a difference...vapor lock???

Thanks for any help you can suggest.

Dick Reynolds "
 
"Dick... Before rebuilding the

"Dick... Before rebuilding the fuel pump, a increase in power would result if you pumped the fuel primer bulb... but after rebuilding the pump, this would not increase the power?

Previously, was the power increased to what it should be, or just a slight increase?

Joe
"
 
" Joe:

I really don't k


" Joe:

I really don't know what the increase was, it seemed to be full power, but I didn't pump it that much, only to verify that it did run faster while pumping.

After the fuel pump was rebuilt no increase in power occurred when the bulb was pumped.

Dick "
 
"If you have access to another

"If you have access to another fuel pump, I'd suggest that you install it to compare running qualities. No offense intended but it sounds like something in that fuel pump isn't as it should be. If you changed nothing else, in my opinion, pumping the fuel bulb should still make a difference. I'm assuming that your engine at the present time is running as per your initial post.

Joe
"
 
Joe:
I noticed that I didn&#


Joe:
I noticed that I didn't finish my spark plug description. I have Champion RJ12C in my motor.

Dick
 
Joe:
I want to finish the d


Joe:
I want to finish the description of the spark plugs in my motor. Champion RJ12C.

I'll be on vacation til the middle of July. When I get back I'll try what you told me to do any let you know the results.

Thanks for all your help.

Dick
 
"Dick.... I have no idea as to

"Dick.... I have no idea as to what that s/plug is but it sounds better suited for a I/O, a inboard, or a 1988 Ford <grin>. In short, that s/plug is no good for that engine! Buy and install two (2) Champion Spark Plugs J6C, and set the gap at .030.

Joe
"
 
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