FD 10 stalls at low idle

[thephoneman]

I was having this issue last fall when I go the boat and motor. So far I have replaced coils, points, and condenser, wires and plugs, as well as lines from tank connector to motor. Blew carb out with air. Good pressure from tank.

Here is what happens: turn tiller to left until it stops (between start and fast). Some pulls the tiller handle pulls back towards shift and slow. Once I get the motor running it will stall if the rpm/throttle gets too low (also if you turn tiller towards shift). Have inspected both mix needles and the low has a little wear below the point but still has a good point to it.

I'm basically a weekend warrior, and have searched the forums for advice but have had no luck. Any suggestions on what to try next? I can post pictures if needed.
Thank you!

 

[HighTrim]

Re: FD 10 stalls at low idle

What is the compression?

Strong blue spark with a real SNAP on the adjustable tester that will jump a 1/4" gap?

Definitely running on both cylinders?

 

[thephoneman]

Re: FD 10 stalls at low idle

I ran a basic inline spark tester and it showed spark on both cylinders. I did a compression test (3 or 4 pulls) and got roughly 80 on both.

 

[racerone]

Re: FD 10 stalls at low idle

When you installed the new coils did you line them up properly or did you just tighten the screws and call it good ?------Heels rubbing on the flywheel will turn the throttle down as you say it does.

 

[thephoneman]

Re: FD 10 stalls at low idle

Just tightened then down. I did have to adjust one as it was hitting the magnet on the fly wheel. How would I go about lining them up?

 

[nwcove]

Re: FD 10 stalls at low idle

compression is slightly low, but it could have used another pull or two maybe. if the spark tester you are using is one of those neon types, it wont do the job as needed, you should use an open air tester. is the throttle arm on the carb synced to the cam? have you rebuilt the carb? lastly, dont pay much attention to the " slow, shift, start " markings on the tiller. pretend they dont exist and go by ear.

 

[nwcove]

Re: FD 10 stalls at low idle

lotsa good info in the top secret file at the beginning of this forum
http://forums.iboats.com/engine-fre...-change-coils-set-points-old-omcs-294072.html

 

[thephoneman]

Re: FD 10 stalls at low idle

The spark tester is one with a little light bulb inside (got it at harbor freight).I believe the cam is synced...not sure what you mean. I haven't rebuilt the carb but things look clean and it appears that it was rebuilt at one time.

 

[nwcove]

Re: FD 10 stalls at low idle

the neon tester will tell you that you have spark, but it wont tell you if its a good strong spark. on the cam that opens the throttle when you twist the grip, there should be a mark ( maybe two close together), the butterfly in the carb should just begin to open when the arm touches the mark ( or is in between the two if there are two). the cam has a bit of adjustment to accomplish this. i would strongly suggest doing a proper carb cleaning a rekit , there are some very small passages etc that can become restricted with gunk.

 

[oldboat1]

Re: FD 10 stalls at low idle

second the suggestion for a carb cleaning.

there is a flat arm up under the magneto on the right of the powerhead, pointing toward the rear -- connects to the throttle control cam with a spring clip. That clip may be missing or loose, and that can account for some strange stuff. If the throttle position is changing while you pulling on the starter cord, that might be it. Look over at the right side when pulling it over, and see if the spark plug wires are moving and/or the armature plate control lever is moving (the vertical post on the right side).

If you want to see if you can improve running without disassembly, try some additional adjustment of the low speed needle. If the motor is running now, start it a let it warm up at whatever idle position is working for you. Then see if you can carefully idle it down some. At the lowest idle where it currently keeps running, adjust the needle 1/8 turn clockwise (leaner). RPMs should increase. Idle the engine down further, and lean out the adjustment a bit more (these are slight adjustments). When RPMs increase, lower the idle speed again. Look for point where the engine will run at a low idle, and increase the rpms. If engine stalls, set the screw 1/8 turn richer and try it again. etc. etc.

It's a trial and error process to find the sweet spot.

Just another weekend warrior here too....

(btw -- compression check, per above posting, if you haven't already. Also, mix should be 24:1.)

 

[thephoneman]

Re: FD 10 stalls at low idle

One other thing i have tried is holding the throttle open while turning the tiller down and it does the same thing (dies out). I'll check the secret file and other suggestions and let you know if I get anywhere.

 

[oldboat1]

Re: FD 10 stalls at low idle

yeah, sounds less like a carb issue the more you describe it. Maybe problems with installation of coils (Racerone, above) or maybe the seating of the armature plate after replacing plug wires. Sounds like it's probably due for a carb rebuild, but that aside it might be a good idea to pull the flywheel again, lift the plate and check the positioning of new plug wires as well as wires on top of plate (tucked away, no rubbing or binding), check assembly of coils, points, condensors, and reattachment of armature plate -- basically check everything that was moved or reattached in doing the magneto work.

 

[HighTrim]

Re: FD 10 stalls at low idle

Compression is low....once running try a heavy decarb.

Verify that it is running on both cylinders. Run it, then pull one plug wire at a time. You should hear a noticeable drop in RPMS. If there is no change, that cylinder was not running.

Get yourself a proper adjustable gap spark tester as well. The neon ones are good to show erratic spark while running, but do not verify that a cylinder will spark while under compression. YOu need it to jump that 1/4" gap.

 

[thephoneman]

Re: FD 10 stalls at low idle

Ok I have somewhere to start. I'll keep you posted. Thank you all very much for sharing your knowledge and experience!

 

[racerone]

Re: FD 10 stalls at low idle

Pull the bypass covers to look at pistons and rings.-----Hook up a timing light and observe spark on each cylinder to see if spark goes away just before it dies.