A little 2-stroke help

[devino246]

My uncle and I have been trying to get his old Chrysler Striper boat running right, and I don't know enough about 2-strokes to diagnose.

It's bogging down at anything past 1/2 throttle. Every once in a while, if you give it 3/4 throttle or so for a few seconds, you can feel the RPM jump and the boat will start to get up on a plane. I've been suspecting a rich condition, as hitting the choke has no effect and the primer bulb stays firm. The engine also produces a fair amount of blueish smoke. Compression checked out good, float height is correct, carb has been cleaned. Plugs are also new, as are the coils. I'm stumped to say the least.

I've got some pics that I'll post up tomorrow. It's a 45hp, 2 cylinder engine.

 

[FatCat]

My uncle and I have been trying to get his old Chrysler Striper boat running right, and I don't know enough about 2-strokes to diagnose.

It's bogging down at anything past 1/2 throttle. Every once in a while, if you give it 3/4 throttle or so for a few seconds, you can feel the RPM jump and the boat will start to get up on a plane. I've been suspecting a rich condition, as hitting the choke has no effect and the primer bulb stays firm. The engine also produces a fair amount of blueish smoke. Compression checked out good, float height is correct, carb has been cleaned. Plugs are also new, as are the coils. I'm stumped to say the least.

I've got some pics that I'll post up tomorrow. It's a 45hp, 2 cylinder engine.

I'm taking it this is a Chrysler outboard boat engine? You should have some blue smoke with a 2 stroke. Not tons though. When your at speed it should be clear behind you. Very little if you see any smoke. What are you mixing the fuel at? Is that what the service manual recommends? It sounds like you've covered most bases. Maybe the timing isn't advancing? This would cause this problem. The choke should stall the engine down. That's weird.
Go over all the electrical. Plug wires and so on. Look for cracks.

 

[HellSpawn]

I'm taking it this is a Chrysler outboard boat engine? You should have some blue smoke with a 2 stroke. Not tons though. When your at speed it should be clear behind you. Very little if you see any smoke. What are you mixing the fuel at? Is that what the service manual recommends? It sounds like you've covered most bases. Maybe the timing isn't advancing? This would cause this problem. The choke should stall the engine down. That's weird.
Go over all the electrical. Plug wires and so on. Look for cracks.

Going to x2 on the pre-mix point. I accidentally mixed a batch for my outboard last year that was stupidly rich, Same exact symptoms you have.

 

[cumminsbayou4x4]

whats your mixing ratio

 

[devino246]

I can't remember what the manual calls for, but my uncle's been following it, as far as I know. Odd thing is, the top plug keeps fouling, but the bottom always stays clean.

 

[machinist@large]

I can't remember what the manual calls for, but my uncle's been following it, as far as I know. Odd thing is, the top plug keeps fouling, but the bottom always stays clean.

From your photo's, this has one carb but two ign. coils? Have you tried swapping all the connections from one coil to the other, and see if it starts fouling the other plug?

 

[devino246]

From your photo's, this has one carb but two ign. coils? Have you tried swapping all the connections from one coil to the other, and see if it starts fouling the other plug?

We might have...I can't remember. I'll try it.

 

[devino246]

In case you can't tell from the picture, I got it figured out: running to lean. Closing the choke partially will let it open up all the way and get the boat up on a plane. One of the pieces on the carb that holds he float is broken and is letting the float sit diagonally. Taking it to a machine shop to see if they can do something about it. If not, hopefully I can find a replacement carb.