67' 9.5 with trouble idling.

[thx997303]

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.

Edited to add: 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.

 

[thx997303]

Re: 67' 9.5 with trouble idling.

Just threw a cheapy inline spark tester on it, didn't seem to be a difference between the two cylinders as far as spark is concerned.

Could the reeds be a problem?

 

[cajuncook1]

Re: 67' 9.5 with trouble idling.

thx997303,

Due the compact style of the motor and low profile design, it sits low. So, what ends up happening is the motor's carburetor inhales a lot of exhaust and idles poorly in a barrel/can. I have a couple of suggestions that other forum experienced guys have given.

1. Put the motor on boat and start it up at the lake and do your slow idle needle adjustments there. Open area and no recirculation of the exhaust by the motor.

http://forums.iboats.com/showthread.php?t=167352

2. Get a fan up near the motor and and have it blow the exhaust out and away from the barrel and motor.

If your are running the motor out at the lake with the cover/cowl on and your motor is running poorly, try running the motor without the cover/cowl off. If your motor runs better, then you may have a exhaust leak problems, which is common with this motor.

Three common areas of exhaust leakage were: (look at the diagram)

1. Exhaust housing seal
2. Exhaust hose
3. Boot shift rod

There are guys on this forum that are experts with your model of motor and hopefully they will chime in to help you out. I though I would offer a penny's worth that would be simple.

Good luck my friend,

cajuncook1

 

[cajuncook1]

Re: 67' 9.5 with trouble idling.

Edited to add: 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.[/QUOTE]

Get a carb kit and pull the plugs and clean it well. Even if there is a little bit of slug or trash your carb will give you trouble.

cajuncook1

 

[thx997303]

Re: 67' 9.5 with trouble idling.

I have a carb kit, and I was wondering if it might suck exhaust.

Still doesn't explain why it will run off of the top cylinder and not the bottom.

 

[thx997303]

Re: 67' 9.5 with trouble idling.

Bump. This forum moves fast.

 

[thx997303]

Re: 67' 9.5 with trouble idling.

I was just pulling the carb off of the 9.5 and couldn't get to the last screw on the bottom half of the carb where it mounts to the intake manifold just above the reeds.

I tried to open the throttle more, and with a small amount of force, the throttle opened up quite a bit more than it ever had before.

Previously, it had only opened just a bit farther than the start mark on the throttle, now it opens all the way to where it says fast. Now that it has opened, it opens to WOT without an issue.

So, I now know that my breaker point gap is off as they are supposed to be adjusted at WOT according to my understanding. So I'm going to redo the gap on the breaker points and see how it runs once it's in time.

 

[kbait]

Re: 67' 9.5 with trouble idling.

Points adjust to the cam.. Throttle position doesn't matter.

 

[thx997303]

Re: 67' 9.5 with trouble idling.

Okay, good to know I don't have to tear into it that far.

I recleaned my carb, and the low speed jets MAY have been dirty. So I'm going to get it in the tank and see if anything changed.

 

[thx997303]

Re: 67' 9.5 with trouble idling.

I put the motor in the tank and ran it with the cowl on, and I was able to get it to idle around 800-900 RPM.

Seems like I need to get it on the water and do a final adjustments of the low speed mixture now.

 

[kbait]

Re: 67' 9.5 with trouble idling.

Sounds like you got it. Congrats!