Yamaha F9.9 4 cycle wont start

[canuckcorsa]

I have a 2006 yamaha F9.9 4 cycle with less than a hour on it. It was running fine when it went for a brief swim in a fresh water (while running). I drained the oil (3 times), I drained the carb (twice), I replaced the gas with fresh gas, I checked the compression (110 on both) and checked for spark. The spark looked a bit weak (I'm used to working on cars) but it was there. I ran it with the plugs out using a drill and it turns over fine. However, after doing all of these things it still won't start. Occasionally it will fire and I noticed that when it did, it kicked back really hard on the starting rope and it puffed out of the carb. I'm new to outboards and boating in general but a pretty good hobby-grade car mechanic and If this was a car I'd say the tming was off but I don't see how that could happen. I've checked for a shop manual and can't find one anywhere.

Any help most appreciated! It was a real sweet motor before this and I just bought a new inflatable for it!

Thanks,
Bob

 

[JB]

Re: Yamaha F9.9 4 cycle wont start

Went for a swim, huh?

Kicks back and puffs through the carb suggests that timing has shifted. Check the flywheel for a sheared key, check cam timing for a jumped cam drive.

 

[garyN]

Re: Yamaha F9.9 4 cycle wont start

Bet you the carb is "gunked up". Happens very easy. Once mine ran fine on the way out - then plugged up and did what yours is doing.

Also can be a broken of clogged fuel pump diaphram.

Get ready to pay a few hundred $ to have it cleaned and then be prepared to do it over and over.

Please see my post, They should put wing nuts on these carburators.