No compression- bent pushrod

wakeup 19

wakeup 19

Member
Nov 14, 2008
678
(Medford)Boston Harbor to Cape Ann to Cape Cod and
Boat Info
1992 300 Sundancer, Quicksilver ding w/ 6hp merc 4 stroke, anchorlift windlass, extended swim platfo
Engines
t/ 350 merc's (carburated) alpha drives gen II
Having a hell of a summer so far.....
1992 5.7 running rough loosing power. Changed cap and rotor, no change. Pull plugs all look fine so did I compression check. #6 has no compression 0. All other are 125-150. 600 hours salt water eng that is stored in brackish river.
Rockers are moving valve doesn’t appear stuck but did hear clanking sound about a week back. Manifolds and risers new last year. May have had slight intrusion but ran great till now.
Last night backed off rockers and exhaust valve rod is bent. Riser off as well. I can blow into spark plug hole and air comes up exhaust manifold. Tapped on valve no change, if it was stuck maybe free not sure.
Don’t want to do heads on 9 year old engine but want to get opinions on next step.
I hope I didn’t miss anything. Thanks, Rob
 
Leaning that way wondering if anyone had similar situation and was able to put in new rod and what were results.
Or anything I am missing.
 
If the valve is closed and you are blowing air through the exhaust, you have a bent valve or some seat problem going on....air should not get past. Pull the head.
 
You have a head issue and you don't want to pull the heads on a 9 year old engine
 
scoflaw said:
You have a head issue and you don't want to pull the heads on a 9 year old engine
Click to expand...
Werent you the guy telling me get a new long block??
I look at it and say got to do 2 heads if one, probably 800 parts etc. same old block. Heads usually last about 10 years up here.
 
wakeup 19 said:
Werent you the guy telling me get a new long block??
I look at it and say got to do 2 heads if one, probably 800 parts etc. same old block. Heads usually last about 10 years up here.
Click to expand...
Exactly, so do you want to spend the money on a 28 year old engine ?
 
If the engines are fresh water cooled do the 2 heads. If they are raw water cooled blocks replace the long blocks as they are getting close enough to the expected end of their life anyway.
 
I have a 383 Stroker motor in my boat. Last year it developed a hard miss. Turned out to be a bent pushrod caused by a valve stuck in the guide. Upon further inspection all of the exhaust guides were too tight and the intake guides too loose. I had a valve job done when I lived in another state a couple of years ago and it appears they screwed the pooch on the head job with the valve guides. I had the guides all changed and have had zero issues since. Bill was $400. Motor stayed in the boat and only the heads and manifolds were pulled.

Have the heads done, check elbows and manifolds while off and then go boating.
Shawn
 
NorCal heads are off. Debating on whether to purchase reman heads or have mine done. Leaning towards reman as I have raw water cooled engines. Thanks
 
I bought a boat a few years ago that had no compression on one cylinder.
Turned out to be a tuliped valve.
I only paid $800 for the boat, so I replaced the one valve, and it's been running great for about seven years now.
 
I still can't figure out why people these days think raw water cooled engines are the death? I've ran RWC in fresh and salt water and if properly taken care of, you'll easily get more than 10 years. My advice is redo the heads.
 
My machine shop said looks like head gasket was on its way out. Not worth machining these some water intrusion. Said probably time to get new enginebefore I start of throwing money at this one. Heads are 700 plus gaskets and labor so over a grand. And putting them on 9 year old reman block.
Reman eng 2200 tricky call
If I take that route I am going to add FWC kit. Got to look into these to see which one is best. I was told I can only do half kit. Not sure why but I have alpha outdrive. Any info appreciated.
 
wakeup 19 said:
NorCal heads are off. Debating on whether to purchase reman heads or have mine done. Leaning towards reman as I have raw water cooled engines. Thanks
Click to expand...
I would do whichever you feel the most comfortable with. Shouldn't be too much difference in price.
 
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