"I’ve trying to solve the abov
"I’ve trying to solve the above problem, todate without success. Motor starts fine runs rough on idle when cold, and goes okay but is down on power. Won’t idle when hot.
When I check the motor, the middle port cylinder has emulsified oil on spark plug. I checked compression to see if it might be the cylinder head gasket, but all cylinders within 5psi. As a matter of course I replaced cylinder head gasket and cleaned out extensive emulsified oil gunge in this cylinder. Ran the boat on the water for an hour or so but made no difference to power or bad idle, so I replaced exhaust plate gasket which I thought may have been the source of the water ingress but again made no difference, except it seemed to have slightly improved power. All cylinders have a good spark, and I have replaced this cylinders lead.
I pulled inlet cowling and started motor and noticed blow back through this cylinder’s carb together with emulsified oil. Removed carbs and reed block and found one petal missing from this carb’s reed valve (horizontal type). I assume the engine has gobbled this petal up!! The crank case cover was also silted up with salt deposits which had completely blocked the bleed tube connection to this inlet. All other reed valves look like new, but some rusting to the screws.
I’m intending to replace the broken reed valve and see if this resolves the issue, but I can’t believe this will as where is the water coming from? Is it possible with a defective reed valve to suck exhaust cooling water up back into the exhaust manifold and then into the cylinder and out though a broken reed valve!! or is there something else I might have missed. Any help much appreciated, as I fear the block might have a crack somewhere.
Rocket"
"I’ve trying to solve the above problem, todate without success. Motor starts fine runs rough on idle when cold, and goes okay but is down on power. Won’t idle when hot.
When I check the motor, the middle port cylinder has emulsified oil on spark plug. I checked compression to see if it might be the cylinder head gasket, but all cylinders within 5psi. As a matter of course I replaced cylinder head gasket and cleaned out extensive emulsified oil gunge in this cylinder. Ran the boat on the water for an hour or so but made no difference to power or bad idle, so I replaced exhaust plate gasket which I thought may have been the source of the water ingress but again made no difference, except it seemed to have slightly improved power. All cylinders have a good spark, and I have replaced this cylinders lead.
I pulled inlet cowling and started motor and noticed blow back through this cylinder’s carb together with emulsified oil. Removed carbs and reed block and found one petal missing from this carb’s reed valve (horizontal type). I assume the engine has gobbled this petal up!! The crank case cover was also silted up with salt deposits which had completely blocked the bleed tube connection to this inlet. All other reed valves look like new, but some rusting to the screws.
I’m intending to replace the broken reed valve and see if this resolves the issue, but I can’t believe this will as where is the water coming from? Is it possible with a defective reed valve to suck exhaust cooling water up back into the exhaust manifold and then into the cylinder and out though a broken reed valve!! or is there something else I might have missed. Any help much appreciated, as I fear the block might have a crack somewhere.
Rocket"