Cd -18 Combustion issue.

Hi Everyone,

I'm new at all of this so I'll tell you as quick as I can .


I recently purchased a CD-18 5.5hp I beleive it's 1961

I purchased it early this spring and it was starting no problem.

I brought it home and started on the 2nd pull....

I ran it with a snorkle on and off for about 20 minutes at varios rpm with and without the trans engaged. Ran great.

The next weekend I took it for a test run at the local waterway.
It started up right away for about 3 minutes, then I think I flooded the motor out and tried starting for about 30 minutes on and off..

Since then I have not been able to get it to fire.

Both plugs are firing fine so I'm assuming the coils plugs and wired are ok.

Compression feels ok (though I have not actually tested it- I 'm use to 2 stroke dirt bikes)

Plugs are getting wet when I try to pull start .

They were a little dark when i first took them out so I cleaned them up and changed the mixture out the forums recommended oil ratio.....( I cant actually recall it as I'm piosting this thread)

Not sure when it was last maintained.

That's all I have to start...any help here would be greatly appreciated,

Re: Cd -18 Combustion issue.

If it is flooding out, and the carb has not been rebuilt in a while, or ever, it might have an old cork float that has lost its coating. The cork then absorbs the gas, looses it boyancy (sp?) and does not close off the inlet needle, thus flooding the motor. So from what you have stated, I would suspect the carb float. I don't know that motor off hand, but if it has a separate gas tank with single fuel line and a primer bulb, you can test the seat by pumping the bulb. If it does not firm up and gas leaks out of the carb, then it is either the float, or something is stuck in the seat.

Re: Cd -18 Combustion issue.

Yup - clean carb and install a new carb kit and float.

Re: Cd -18 Combustion issue.

Both plug firing, plugs getting wet.

If the carb is not flooding then check the flywheel for a sheared key, that would shift the timing and not run. Depending on how much it change it may or may not fart, pop or give any other sign other than wet plugs.