350 engine problem 5.7
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=4550
Printed Date: November-27-2024 at 11:17am
Topic: 350 engine problem 5.7
Posted By: eric lavine
Subject: 350 engine problem 5.7
Date Posted: August-19-2006 at 10:27am
kinda correct craft related, hour meter 179, 2nd engine, 3 and 5, 4 and 6 burned up cant figure out problem, anyone ran accross this? wot 4400 rpm. the boat belongs to a an ex marine mechanic and insists the boat is propped correct. anything would help
eric
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"the things you own will start to own you"
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Replies:
Posted By: GottaSki
Date Posted: August-19-2006 at 10:45am
The engine can take another 1k-1500 rpm before becomming concerned about rpm...
But first impression is it ran lean for too long, Like a main jet was incorrectly sized or partially blocked, or detonation/preignition. It should have has some mis performance symtom beforehand.
Replacing the engine again without investigating the carb will be exspensive again.
Alternatively, if the replacement engine was assembled with automotive piston-bore clearance, the bores will score. Due to extended loading and heat, the pistons swell more, requiring more clearance.
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"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."
River Rat to Mole
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Posted By: Munday
Date Posted: August-19-2006 at 11:39am
If its the 2nd engine that burned the same way.
And cooks only the inner cyl.I'm thinkin cooling problem like the head water passages are wrong or wrong head gaskets.Course need alot more information,like were they the same heads and block rebuilt,how do you mean cooked did it loose ring tension and go to smokin or spin the rod inserts?
Munday
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Posted By: eric lavine
Date Posted: August-19-2006 at 11:41am
he re-propped and never could get the rpm's over 4400, even with the new merc supplied long block (same carb and intake)I think with what your saying and to big of a prop this may be the problem? a valve seat was dropped on 3, and between 3 and 5 the head gasket was bur'nt right thru. he insists the boat is propped correct, i think he should be able to hit 4800 rpm,s (when engine is running correctly)i will thouroughly investigate the carb and intake before i sign my name to this one.
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"the things you own will start to own you"
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Posted By: eric lavine
Date Posted: August-19-2006 at 11:47am
i do see on the intake the paint is burned on both sides right in the center, he had the identcal problem on the first engine in which it was replaced under merc warranty. brand new long block.
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"the things you own will start to own you"
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