300/440/550 JS550 is a bitch to restart

[dean85gt]

So my 84 550 has been giving me some issues. It runs great and starts right up from cold. If I am running it and shut it off it is an absolute bitch to restart. I usually end up draining the battery and/or fouling the plugs. It will only start with the throttle held wide open so I know it is flooding out. What can this be?

Thanks

 

[Flat Brapp]

Low Compression sounds like an issue. Get yourself a good tester and see what it is. Lower than 120 psi usually will lead to hard starting.

 

[Motorheads5]

I think you need to kit the carb but do a compression test like Brapp is saying so you can see if it is good or bad. You are right though it is flooding otherwise it would not help to give it more air, probably a bad seat or needle.

 

[dean85gt]

compression is 150psi in each cylinder

 

[the WaTeRhAwK]

that's decent for a stocker. what carb are you running?

 

[dean85gt]

as far as I know its just the stock one....stock exhaust stock everything enginewise

 

[the WaTeRhAwK]

as far as I know its just the stock one....stock exhaust stock everything enginewise

that doesn't mean anything specific. does it have 3 bolt holes in the top, or 4?

 

[dean85gt]

ahhhhhh not sure that is something I will have to check tomorrow...let me look for a pic in the meantime

 

[Motorheads5]

subscribing lol

 

[the WaTeRhAwK]

subscribing lol

you were already subscribed..lol

 

[the WaTeRhAwK]

I'm thinkin the popoff is too low, or the needles are out of adj.

 

[Motorheads5]

I don't think it makes any difference which carb he has. The problem is the same.

 

[the WaTeRhAwK]

well, if his popoff is too low, it would cause it. the reason I'm wondering which carb he has is to make sure his settings are correct.
if it is in fact a fuel issue, the reason it starts fine from the get-go is because the excess gas has had time to evaporate, then after he gets into running it a bit, it's loading up again.

I've had them exhibit the same symptoms with a warped cylinder head, also. the thing would start and run fine at first, then heat up and start running like crap and be difficult to start until it cooled off and the metal retracted.

 

[Motorheads5]

Ok

 

[the WaTeRhAwK]

if he's getting 150 per cylinder, it's definitely not the compression.
if I'm not mistaken, the stock specs on an '84 is 155 psi.

 

[dean85gt]

Stock specs in the manual are 128! lol

 

[jetsport484]

Just a thought when was the last time the crank seals were replaced?

 

[the WaTeRhAwK]

Stock specs in the manual are 128! lol

yeah 122 to 155, so if you're getting 150 it's in pretty good shape. depending on year model. the domes are cut different on different year model engines.

 

[dean85gt]

Not sure on the crank seals I just got the ski a month ago. Apparantly the motor is recently rebuilt though...which I believe because of the high compression. It had a butch's ski shop sticker on it when I got it and I gotta say it goes pretty damn good.

 

[dean85gt]

The flame arrestor adapter has 3 bolts that go onto the carb..I hope that helps a bit.

Also, Can the crank seals be bad and the engine show compression that good? I honestly havent left the ski to sit for an hour and try to fire it again. When I start it from cold it always fires right up.