| Title: | Powerboats |
| Notice: | Introductions 2 /Classifieds 3 / '97 Ski Season 1267 |
| Moderator: | KWLITY::SUTER |
| Created: | Thu May 12 1988 |
| Last Modified: | Wed Jun 04 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 1275 |
| Total number of notes: | 18109 |
My 1986 260 Mrec just sucked and exhaust valve and is going to cost
me big bucks to fix. I spoken with the guys in the shop and nobody
can really tell me why. The engine has never overheated,I run usually
around 3600 to 3800 rpms and I have faithly changed oil and filter
every 50 hrs. The engine never had as much as a tap and was running
well on the day it happened.
I only have 373 hrs on the engine and everyone I've talked to is
amazed that this happened. I've never been one to add anything to
any engine fluids except maybe the dry gas at the begining and end
of the season. I guess the question is should I have been using
a lead additive. I thought the newer marine engines were set up
to use the no lead fuels.
Any comments or suggestions are welcome.
Thanks
Walt
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 507.1 | Not all that surprising | BIZNIS::CADMUS | Fri Sep 08 1989 10:52 | 27 | |
Is the 260 based on the small block Chevvy engine? If so, the max rpm
on that engine is arouind 4200. running 3600 --3800 rpm is pushing that
engine kind of hard. In a car ( or truck, which the engine is based on)
That's akin to diving up a VERY steep hill at about 70 mph.
I have a 350 chev in my boatI find I get the best performance(
economy) at around 3000-3200 rpm. Having had more than my share of
sometimes specatcular major engine failure, I tend to be somewhat
gentle on my engine.
Running an engine at those rpm's with a high load such as in a boat
for extended periods of time often results in failure. THe recreational
boat engines are usyually LT ( Light truck based blocks, although some
mercruiser 4 bangers are based on a 4cyl ford trctor. The
tractor/industrial based marine engines are designed to run at full
load continuosly, while the truck and automotive based engines are not.
If you engine bought the farm - you can replace the block/heads with
GM lighttruck components-( I am still assuming you have a GM small
block v8 based engine) with the block and heads- the main differnces
are different ( marine ) head and intake manifold gaskets and brass
core ( freeze )plugs.
D................
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| 507.2 | BAD VALVE | THOTH::WRIGHT | Fri Sep 08 1989 14:08 | 10 | |
HI I HAVE A 205 4WINNS WITH A 175 HP I LOST AN EXHAUST VALVE ALSO.
THE REASON WAS THAT WHEN IT WAS TUNED UP FOR THE SEASON THE GUY
PUT THE WRONG PLUGS IN,MUCH TO HOT. THE MOTOR NEVER OVERHEATED.
THIS WAS NOT COVERED BY MY WARRANTY. THE GUY WHO DID THE WORK HIS
INSURANCE TOOK CARE OF IT. THIS IS WHAT HAPPENED TO ME THE COST
WAS JUST UNDER $700.00 90% OF THAT WAS LABOR. MY ENGINE HAD APPROX
30 HRS. GOOD LUCK!!!!!!!!!!!!!!!!!!!!
BOB W
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| 507.3 | 260 Mercruiser = 350 Chevy | CLOVE::KLEIN | Mon Sep 18 1989 13:13 | 20 | |
Actually, chewing up a valve after 373 hours of relatively hard
running is not that surprising. As mentioned previously, the motors
are designed to 'max out' around 4200 (or so) ... so running around
in the top 90% of the motor is pretty stressful.
And yes, the 260 Mercruiser is a stock 350 Chevy block with various
marine components added.
Mercruiser has recently had problems with their valve trains - the
365 Magnum (big block Chevy) seems to have a large appetite for rocker
arms. The 260 seems to have been (via anaecdote only) relatively
trouble free.
One thing that I've done to extend engine life is to get a teflon-based
product and add it to the motor oil.
Mitchell
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