9.9 Honda (2001) Dies when I open the throttle beyond quarter revs.

arthurpavlovic said:
Hello again,

After a few days cleaning and replacing components in the fuel system, I am now convinced that there is an intermittent problem with the spark. on two occasions it has started on one cylinder, or not at all! When I replace the plugs, it runs fine. Put the first set of plugs back in, and it still runs fine! John the Kiwi might be right it could be the electronic ignition, but I am hoping that it is the HT leads (probably just one of them). (When I change the plugs, I move and usually clean the leads.) So, if nobody has any better ideas, I will order HT leads. Because the fault is intermittent, I do not see how I can test them. Ideas anybody?

On the positive side. When it runs, it runs great, and I found out how to remove the governor that Honda so kindly fits to the 9.9 hp. So, now I have a Honda 12 hp (or thereabouts).
Click to expand...

You are saying that it always runs fine on the old plugs ?

and that it suffers from intermittent failures with the new plugs.

Id suspect the new plugs........ I had dodgy new plugs for a car once..... and even replacing those caused the same trouble because the second new set came from the same batch.

You are sure the new plugs are the correct type and exactly the same as the old ones.

You could try inline spark testers .
 
i`ve got exactly the same problem with a 2001 suzuki df 9.9! had a problem with the connectors to the tank too, then it dies when you rev it, then ran on one cylinder, also made a loud `pop` twice`. reading this with interest as still havnt sorted it!!
 
Hi VicS,

Thanks for the interest.

I am saying that the problem is intermittent. The very act of changing the plugs seem to solve the problem. It does not matter which plugs I put in. Then next time I go to test the engine, it may not start, or just only run on one cylinder. So, I put the old plugs back in, and it runs beautifully. Therefore, it seems to me, that something involved with changing the plugs is solving the issue. Ergo, maybe by moving the plug caps, or HT leads, it might make a connection. So I think it might be worth changing the plug caps, if that does not work, then the HT leads. Thanks for making me be clearer. the more I think about it, one of the plug caps has a minor fault, which I may have discounted.

Thanks Vic, best wishes,

Arthur
 
Hi elioti,

It is all good fun is it not. Spray carburetor cleaner, fresh fuel, new tank, line and bulb, has eliminated the fuel supply issue for me. Today, when she would not start, changed the plugs. Had muffs 'insulating taped' on and she roared like a spitfire, even with violent throttle movements. (No loud 'pops') so I believe my issue is electrical. There is a short somewhere. Hopefully inexpensive.

Best wishes, and good luck,
Arthur
 
It might be a bit late now, but why not have it serviced by a Honda specialist .... I messed around with a small Honda 4stroke for a couple of years. Honda service, and a new carb, and it was right as rain. Yours sounds like mine from what you are saying.... I'd suspect the carb is gummed up, and carb cleaner isn't up to the job.
 
arthurpavlovic said:
Hi VicS,

Thanks for the interest.

I am saying that the problem is intermittent. The very act of changing the plugs seem to solve the problem. It does not matter which plugs I put in. Then next time I go to test the engine, it may not start, or just only run on one cylinder. So, I put the old plugs back in, and it runs beautifully. Therefore, it seems to me, that something involved with changing the plugs is solving the issue. Ergo, maybe by moving the plug caps, or HT leads, it might make a connection. So I think it might be worth changing the plug caps, if that does not work, then the HT leads. Thanks for making me be clearer. the more I think about it, one of the plug caps has a minor fault, which I may have discounted.

Thanks Vic, best wishes,

Arthur
Click to expand...


Or maybe you are disturbing the low tension leads as you wiggle things?
Just to expand on the problem i had: I could start the motor only by wiggling the wires where they entered the multiplug on the CDI unit between each pull on the rope. Finally it would start.
Once running it would keep running but i could stop the motor by flexing the wires near the multiplug. Now the CDI has male pins and the whole thing is a solid block of electronics mounted in an epoxy filled box right? No room for dodgy connections internally in the CDI right? Thus i reasoned and thus i bought a new wiring harness and fitted it with great expectations. Wrong! no improvement at all.
That's when i gritted my teeth and bought the new CDI.
End of problems. Starts 2nd pull mostly and first pull sometimes even after a month or two of winter holiday.

Best of luck
John
 
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