strange problem

[crash5600]

I have a 1976 9.9 Evenrude modle #10624.

Idols fine for trolling but when wide open it seems to run rough and a lag, not smooth, untill I pull the choke out fully then it not only runs smooth but picks up speed. Regardless if the choke is in or out at full throttle I have to bring the revs down VERY slow or it stops and is hard to get going again.
It has been this way as long as I have had it about 10 years
Tryed new plugs no diff.

Someone said it might be the spark plug gap??
Does anyone know what the gap should be and the correct plug for that matter? just incase I have that wrong!

I run a 50 to 1 mix is this right?

 

[samo_ott]

Re: strange problem

Yes, it is 50:1

Usually if you need to use the choke to help it run it means it's not getting enough fuel in the standard running condition. This usually denotes a carb issue. So the standard fix is to take the carb off and clean it, especially the high speed jet and reinstall.

 

[mikesea]

Re: strange problem

ditto what steve said,the carb float may need adjustment too,sounds like it sucks the fuel from carb faster than can be replenished,start off by insuring there is no fuel line kinked,or any dirty filter if installed,if the problem goes away when you squeeze the ball its a fuel restriction of some kind

 

[jeff_smith_0423]

Re: strange problem

I second the fuel restriction, either in delivery or in the carb. Clean it.

 

[jeff_smith_0423]

Re: strange problem

Champion L-7J for R suffix motors
Champion UL81J for G&H suffix motors

I don't have a service manual handy but .030 is typical. Someone else can chime in.

Edit: Here's a chart

http://www.boatsetup.com/SparkPlugChart.pdf

 

[crash5600]

Re: strange problem

Ok, I will look at that issue, makes sence thank you all.

JeffHow do I know if I have a R suffix or a G&H suffix moter???

 

[jtexas]

Re: strange problem

The choke restricts the amount of air, creating an extra-rich mixture for cold starting. Choking a warm engine should flood it out and shut it off. If it doesn't, the only possible cause is the carb problem described by Steve.

Restricted fuel lines, faulty pump, spark issues...none of these are affected by the choke. If the carb bowl is empty, choking won't help.

Your model number is on the port side engine mounting bracket -- the last character is your "suffix".

 

[crash5600]

Re: strange problem

Thats what I thought was meant, but what through me is that the Model # ends with C and the serial # begins with C they are the only letters on the plate???

 

[crash5600]

Re: strange problem

????????????????????

Thats what I thought was meant, but what through me is that the Model # ends with C and the serial # begins with C they are the only letters on the plate???

 

[jeff_smith_0423]

Re: strange problem

BRP's parts site doesn't show any C suffix motors in 76, but they do in 75....

...which was an L-7J



Also - I'm still in the "rebuild the carb and check all fuel connections" camp.....

 

[jtexas]

Re: strange problem

any chance your "C" could actually be a "G"?

10624 is definately a 1976.

 

[crash5600]

Re: strange problem

I was looking in the dark with a flashlight so I looked again in the light of day and were I made the mistake is the number its 10524 C NOT 10624C so it is a 1975

Thanks Jeff

I am going to rebuild the carb the same time I replace the reed valve, I asume the reed valve is the same as a leaf valve?