question for I/O guys

cfelton · #1 07-17-2007, 01:52 AM

My buddy has a 86 v20 with a 470 I/O like mine,and the O ring on the exhaust pipe to inner transom plate went bad. So we pulled the motor back about 3-4 inches to get the pipe out. We replaced the o ring ,put the motor backin and now it wont start. We checked ,it has fire, gas in the intake and good compression and the timing is dead on. Its stumped us!Both of us are pretty good mechanics but we cant figure this thing out. What the heck are we overlooking? weve checked everything. Anybody got any ideas? Forgot ta tell ya we pulled a couple of plugs and they were dry. Its like its not pulling the gas into the combustion chamber. I took off the breather and cupped my hands over the carburator throat and its really not sucking in alot. It ran perfect before we pulled the motor back. weve checked the carb base gasket and the intake gasket, they look ok.

Monkey Butler · #2 07-17-2007, 09:27 AM

Don't think it would be caused by moving the motor but what about the timing chain?

Steve P.

spareparts · #3 07-17-2007, 09:51 AM

go back to basics, check compresion, you've checked fire, but put an inline spark checker( the neon one) on it and see if its sparking under compresion, then use a "small" amount of starting fluid to see if its a fuel deliver issue.

One other thing, did you loose the exhaust flapper in the pipe, they can get sideways in the pipe and create a lot of backpressure

C YENSEN · #4 07-17-2007, 10:07 AM

what spare said, and maybe you kinked the metal fuel line when you moved the motor? ???

C YENSEN · #5 07-17-2007, 10:08 AM

is it trying to start or not even clicking? maybe you got a loose wire on the starter from moving the motor???

i would check all connections if it were me ;)

THEFERMANATOR · #6 07-17-2007, 12:34 PM

I'm in agreeance with spare, it sounds like an exhaust issue since you say you have fire and fuel in the intake but none on the plugs and you say it doesn't feel like it is pulling in much air. Take one of your exhaust bellows off and see if it will start.

cfelton · #7 07-18-2007, 02:01 AM

Spare, I think you may be right. When we pulled the exhaust pipe off half of the flapper fell out the bottom. I couldnt find the other piece. It must be hung in the exhaust pipe somewhere. Ill go by his house tommorrow and check it out. Thanks

spareparts · #8 07-18-2007, 09:39 AM

pull the prop off first, they usually get stuck behind the prop, if not there, pull the drive, look right behind the shift shaft