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Tulip valve

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Patrick Isaac

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"If anyone has any idea on thi

"If anyone has any idea on this please help me. I had a 5.0gi Volvo engine in my boat, it was a used boat with about 80 hours on it. I put about 80 hours on it in one season and had no problems with it. before I winterized it, it froze, but I found no visible damage from that. I put the boat in the water ran it for about 6 hours with no problem. Then I "tuliped" a valve, number 3 cylinder. I replaced the engine with a 5.7 liter Jasper. I used the intake and distributor from the old 5.0 engine, but I replaced most of the other parts, exhust and so on.. Ran the new engine for about 3 hours and tuliped the same exact valve.
Had a professional work on it, replaced the head and now I get back firing and the engine cuts out when it is moving. When idleing it is okay, but when you start moving it cuts out and back fires. Does the same thing at higher rpms also.
Any idea what could have cause the valves to tulip on two different motors? what is causeing the cut out and back firing? Intake manifold? Distributor? Computer? I have no clue. Thanks,"
 
"The freezing has probably don

"The freezing has probably done more damage than you have located. I would suspect the exhaust system is cracked, and the crack will open more when warm and allow water to enter the cylinder. Since water can't be compressed, you "tuliped" the valve in this case. (it frequently breaks the piston instead) What part of the exhaust haven't you replaced? Engine parts are available at aaamarine.com at discount prices."
 
"I replaced all the exhaust pa

"I replaced all the exhaust parts. Manifold, riser, .
only things that I didnt change are the throtle body and the intake manifold. This engine is a refurb one from Jasper."
 
"Tulip valves are normally cau

"Tulip valves are normally caused by overheating the valve plate, or not properly seated valve. The reason my be a few. Engines that has been stored may bild some surface rust on the sealing area, valve lifter may not work properly, wrongly adjusted valves, restriction plates are not mounted in the intake manifold gasket exhaust passage. For new and engines that has been stored for some time, allways let them run unloaded on 1000 rpm some time to 'clean' the valve seats. Onother culprit might be bad/slow burning fuel after storage.
The backfireing problem might be from wrongly set ignition, broken distributor springs that advances the timing too quick, leaking intake valves that sends the combustion gases into the manifold, crossed plug wires or defective wires, cracked distributor cap .....

Start will all settings and adjustments and doublecheck!!
Then check the valve lifters and valve lash adjustment (contact and 1/2-1 turn).
Use fresh fuel!"
 
So you dont think it is the in

So you dont think it is the intake manifold? I have had a few people tell me it might be a fuel issue. That I may have gotten bad gas and that it may not have run out. I have only run about one and a half tanks of gas through the new engine.
 
"I doubt it is the inntake man

"I doubt it is the inntake manifold itself, but it might be the gaskets used that does not have the exhaust restrictons making the temp in the manifold to high and thereby the mix to lean. Unfortunately as I mentioned there are quite some possibilities. I'm not at the engine to inspect so I can't give You a more close answer, that has to be up to the mechanic.
The only thing that is for sure is that it is caused by overheating the valve plate. If that is caused by 'lean burning' the sparks should bear some signes (white and not slight brownish), if the reson is lack of heat transferr due to bad contact and isolated to a limmited number of valves, the lifter and valve lash should be further examined. If the problem is on one side of a V-engine, it might be poor circulation in the corresponding exhaust manifold .........

I might go on, but hopefully it gives You an idea about what to look for. Just remember that the job is not 'completed' until You have found the reason for the breakdown! If You use a hired mechanic/workshop it is their responsibility to 'complete' the job and not just do random swapping of parts and following innvoices. If they can't explain why a part has been changed, do not pay for it, but remember the part dammaged may not be the one causing the dammage!"
 
"Okay, point taken. I found a

"Okay, point taken. I found a recall on the VP that says to take out the flappers in the Y pipe. It says they can cause damage, but doenst say what damage it causes. One other problem I have is the boat drags getting up out of the water. It used to pop right up, When I removed the props, I could not lock in the second prop, by placing the outdrive in forward or reverse. Almost seems to me that the second or inside prop is not locking in, causeing the outside prop to do all the work and drag the inside prop. If that is the case, could that be the reason the engine runs fine at the dock, but when I take off it runs like a turd?"
 
They (both props) shou

They (both props) should 'lock up' when You put the drive in gear. Perhaps You should take out the nearing housing and have a check.
As for the 'flappers': if they gets loose they may block the exhaust passage out creating an eccesive exhaust back pressure that again may lead to burned exhaust valves and bad performance.
 
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