Help Eliminating the problem

[trita306]

This 72 9.5hp motor I am trying to repair is missing and not holding idle very well. I am a handy person but slightly new to the boat motor realm. Here is a video of the problem:
IMG 3249 - YouTube

What I have done so far:
Changed Spark Plugs
Cleaned out gas and lines
Put fresh gas/oil/foam
Compression Check - 65 in both

My next step is to clean the carbs. Is there anything else I should be looking for or doing?

A few things I noticed:
Impeller is working fine it seems but I will likely change it since I am not sure when the last time it was replaced. The pump bulb to squeeze gas in seems to just suck gas and push it back down to the tank. It does not fill to the point where I cant squeeze it anymore. What do I need to replace to fix this or is this normal?
When I finished running I looked in the water and there seemed to be some oil on top of the water as pictured below. Is there cause for concern?

 

[JRegier]

Re: Help Eliminating the problem

Try adjusting your low speed needle (the knob under the choke handle)
Turn it all the way in until it seats (gently) and then turn it out about 2.5 turns. Start and run the motor and turn the needle back in an eighth turn, each time you adjust let it run for a a few seconds before the next adjustment until the motor starts to sputter, then turn it back out 1/4 turn from there.

And the oil on the water on the water is the way of life for all old 2 stroke motors. Nothing to be concerned about.

 

[racerone]

Re: Help Eliminating the problem

These motors have a habit of cracking the ignition coils.--They then short out to the magplate.----Pull the flywheel and inspect them.

 

[F_R]

Re: Help Eliminating the problem

That motor is "lean sneezing." Could be as simple as the slow speed needle being set too lean. Could also be poorly adjusted throttle/spark synchronization. And of course, there may be an air leak in the crankcase somewhere. Can you see smoke/fuel/fire spitting out any such a leak whenever it sneezes?

 

[trita306]

Re: Help Eliminating the problem

No noticeable smoke/fuel/fire when it sneezes. I will try adjusting the lean/richness tomorrow and report.

 

[trita306]

Re: Help Eliminating the problem

Two things: First, the rich/lean knob only turns 2 total turns.
Second, the idle adjustment knob on the right of the throttle seems to turn endlessly in either direction. Is this normal?

 

[HighTrim]

Re: Help Eliminating the problem

Disconnect the needle from the plastic connector. Then you can have full range of motion. Turn it clockwise to bottom it out, (seat it), then back it out 1.5 turns. Fine tune from there on the water.

I hope you are able to tune it out. I have had a nightmare of a time with a couple of these sneezing at low idle. They can leak air in at a number of locations. fuel line, connectors, throttle shaft, welch plugs,etc... Could also be clogged crank drain? Have fun investigation!

I would definitely pull the carb, clean and rebuild to start.

EDIT: WIll choking it or covering the carb intake with your hand smooth it out some?

 

[trita306]

Re: Help Eliminating the problem

It does seem to help some when the choke is out. I will try putting my hand over the carb tomorrow.

 

[HighTrim]

Re: Help Eliminating the problem

It does seem to help some when the choke is out. I will try putting my hand over the carb tomorrow.

Same thing. That should smooth out a lean sneeze somewhat as it did. Keep looking for the lean condition.

Run it in the dark as well though, can you see arcing out of the mag, wires, etc...?

Have you pulled the flywheel and inspected the ignition yet?

 

[bonzoscott]

Re: Help Eliminating the problem

It may not be your problem, but I would change the points first thing so you know where you stand. You have to pull the flywheel to get at 'em. Set to 0.020. Inspect coils for cracks while your under there. Also not mentioned: Change your lower unit (gear case) oil. Inspect for water / milk at that time.

Opps! Chris mentioned ignition. It's early...

 

[trita306]

Re: Help Eliminating the problem

I have everything to replace the gear oil, I just figured that wasn't relevant to this problem.

Would it be beneficial to just replace the coils to eliminate that possibility?
Also, is there a carb kit or anything I should get when cleaning/rebuilding the carb?

 

[racerone]

Re: Help Eliminating the problem

As far as I am concerned you should test and inspect before rushing out and spending $$-------I often find motors exactly like yours with either 2 new coils installed already or 2 that are cracked with from plastic aging.----Testing and inspection is the path forward.

 

[trita306]

Re: Help Eliminating the problem

Success! Looks like it was as simple as the slow speed needle. I adjusted it and fine tuned it while it was running and voila. Sneezing went away and it seems to be running smooth. I let it run for a while raising and lowing the throttle and it seems to be running smoothly.

 

[JRegier]

Re: Help Eliminating the problem

Same thing was wrong with mine wen I got it except my carb is plugged up so much I had to turn the needle out 10 times.
Needless to say I'm rebuilding the carb this weekend.