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67' 9.5 with trouble idling.

T

thx997303

Member
I have already changed the spark plugs, breaker points and condensers, and removed and cleaned the carburator.

The engine will not run at an idle of less than about 1200 rpm. It will for a minute, but then it will rock as one of the cylinders misfires, then will eventually die.

I did a compression test, and both cylinders were at 60 psi.

I tried squeezing the primer bulb when it was having trouble idling, no help.

I pulled the plug wire off the top cylinder and the engine began running horribly, but continued to run.

I pulled the wire off the bottom cylinder after putting the top cylinders plug back on, and the motor died.

I'm thinking I may need to replace the coils, but can't think of anything else it could be.

I have only run this motor in a square plastic storage container. I have not had it on the water. Also, I have not pulled any of the plugs in the carb.

The throttle would not open further than a little past the start mark on the throttle, but I managed to free it. When I put in the breaker points, I did not set the gap at WOT, not sure if that makes a difference or not.

The carb to intake manifold gasket MAY have been leaking, but I am not sure.

Any suggestions?
 
one item of concern,on those 9.5's,is exhaus smoke in eng compartment,due to a bad big fat rubber seal....try w/cvr off.
 
Make sure the tiny hose isn't cracked or broken under the carb between intake and crankcase. You've probably had cover off when running so I would try spraying carb cleaner or starting fluid around intake manifold area. don't let any mist get into carb intake opening. See if the motor speed changes when you spray. Do this at as low of idle as you can run it and let us know what happens.
 
Check the spark it should arc accross at least a 1/4" gap.

Spark Tester - Home Made)
(J. Reeves)

A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.

Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:


..........X1..........X2

.................X..(grd)

..........X3..........X4
 
Nice tester....they work great! I'm working on another "Stubby" right now with the same problem......I'll let you know what I find out.
 
I re cleaned and re-re-built the carb. I hadn't gotten the low idle jets.

Seems like it idles now. Gotta get it on the lake and see how she does after I adjust the low idle mixture.
 
Great, the float setting should be set carefully as well. Seems about 1 to 1 1/2 turns is most common on these little "Stubbies"
 
Ok, I found very lean cond. at idle with 9.5 I'm working on. Everything else checked out. Great spark and fuel pressure. Can't get this 9.5 to stop "popping". Cleaned carb and tried different carb upper with same results......
will idle but then "pop" about every 5 to 10 seconds.......
I'm gonna have to start a new topic. This "stubbies" got me stumped.
 
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