Took my boat out to the lake Sat. and I noticed the 140 Mercruiser was
running a little bit rough. only at idle,a nd didn't want to start very
well. Still after warm up a bit, it took off doing good. throttle up,
and planed out nicely. ran smooth at 3200 RPM. Ok later my brother said
I had low compression on a cylinder and suggested we run a compression
test. 1-125 lb. 2-80 lb. 3-80 lb. and 4-50lb! CRAP! No sign of water
on the dipstick, but took off the fill cap and it was milky white.
CRAP! Pulled the head and #4 ehxaust valve was burnt pretty badly and
looked like crossfiring between #2 and 3.

SO....to the performance shop it goes, to see if it's cracked, will
pass a flow test, have new high temp valves installed and planed, and
get some new headbolts due to possible streaching.

OK, I've heard pro's and cons concerning using Mercruiser steel head
gaskets. Fel-Pro makes a great head gasket, which is your basic copper
"sandwich" whis has been a really good gasket for automotive use for
years. and some say that is the way to go.

Others say to use only the OE or OE style steel gasket. What would the
the advantage (if there is one) to using the steel gasket ? I can
understand not using the copper alloy in salt water, but this boat will
never hit the salt.

Any suggestions?


Tim

"Tim" wrote in
oups.com:

Any suggestions?


Tim


Engine running LEAN burns exhaust valves in the heat.....fries head
gaskets, piston tops, pre-ignition knock and overheating increase.

Is it left at the dock with full-of-gas float carbs to evaporate into
shellac, clogging all the jets and making it lean as hell? Clogged fuel
injectors do the same thing to FI engines.

Cut off the fuel and run the carbs DRY in any gas engine if you're going to
store it for over a day....keeps the shellac out of those jets!

--
Larry

So many outboards are running so lean.......
inboards, too!

Larry, I thinkt he damage may have been done before I got the baot last
fall. it really amazed me at how well it ran, even though it was a bit
trifle to start. I wouln't have ever noticed the engine loafing at idle
if my brother hadn't told me about it. I know the fuel you get today is
next to crap, and so i do ahve some Sta-Byl that I put in the tank at
every fill.

That does make sense for the carbt o run lean, though. I'll ahve to
check that out too!

Larry W4CSC wrote:
"Tim" wrote in
oups.com:

Any suggestions?


Tim


Engine running LEAN burns exhaust valves in the heat.....fries head
gaskets, piston tops, pre-ignition knock and overheating increase.

Is it left at the dock with full-of-gas float carbs to evaporate into
shellac, clogging all the jets and making it lean as hell? Clogged fuel
injectors do the same thing to FI engines.

Cut off the fuel and run the carbs DRY in any gas engine if you're going to
store it for over a day....keeps the shellac out of those jets!

--
Larry

So many outboards are running so lean.......
inboards, too!

Larry, I had the same problem, it turns out, with the new fuel with
ethenol in it, the engines run lean. Now if your engine is close to
lean, and you burn the new fuel, it can push you over the edge. The
engine starts to detonate, this raises the temp and pressure in the
cylinders dramatically. The end result, burned exhaust valves, blown
head gaskets and bent rods in a very short period of time. When you get
the engine rebuilt, check those rods, you should back off on the engine
timing by one to two degrees, this should stop the problem from comming
up again. Your not the only one to have this happen to them.

John

Thanks John, n Larry.

This thing never did make any spark knock. But then again, I think the
ehad damage was already done before I got the boat.

I didn't realize that about the gasahol. There's very few stations
that sell non alcohol fuel anynmore. One guy that works on small
engines (lawn mowers, weed eaters etc.) told me that some stations will
run up to 15% alcohol in their fuel and it won't even be designated on
the pump, so you don't know if you're getting alcohol or not"

Kind of a bummer really. But there is a place on the way to the lake
that does sell
110 octane racing fuel (+/-) guarenteed not to have juice in it. I
wonder what that would do. It's expensive but cheaper than a blown
head for no more boating than I'll really do this summer.

Tim

"Capt John" wrote in
ups.com:

Your not the only one to have this happen to them.

John


I love my diesel cars, boats, trucks.....
I love my diesel cars, boats, trucks.....
I love my diesel cars, boats, trucks.....

I love my diesel cars, boats, trucks.....

I love my diesel cars, boats, trucks.....


--
Larry

You know you've had a rough night when you wake up and you're outlined in
chalk.

Tim, detonation on a boat is not easy to detect, due to all the other
noise. You really need to know the boat well, but I've been told by
reliable people that it can destroy an engine in as little as 10 hours
of use, that's just a few days out on the water for most people.

In article .com,
"Tim" wrote:

Thanks John, n Larry.

This thing never did make any spark knock. But then again, I think the
ehad damage was already done before I got the boat.

I didn't realize that about the gasahol. There's very few stations
that sell non alcohol fuel anynmore. One guy that works on small
engines (lawn mowers, weed eaters etc.) told me that some stations will
run up to 15% alcohol in their fuel and it won't even be designated on
the pump, so you don't know if you're getting alcohol or not"

Kind of a bummer really. But there is a place on the way to the lake
that does sell
110 octane racing fuel (+/-) guarenteed not to have juice in it. I
wonder what that would do. It's expensive but cheaper than a blown
head for no more boating than I'll really do this summer.

Tim


If gasahol is your problem, then just by 80/85 Aircraft Fuel.
No alcohol in that stuff, but it is a bit pricey for a boat guy....


Me or 100/110 if you want to spend considerably more.....

OK, the head is done,( $250.00 worth) and the machinist said that the
seats were pretty beat up which would recess, and through the valves
out of adjustment.... ie. the valves would lose there lash against the
rockers, and would be forced to stay open even just a couple
thousanth's or so and not close tightly. So it got a pressure test,
plane job, new valves and seats, seals springs tested. New head bolts
and gasket set.

He said that the head was slightly warped in between the 2 and 3 cyl.
and said that sometime in it's past life it boate engine was probably
over heated. Now I did notice that when I went to service the engine
the pump/alternator belt was loose and you could turn the water pump
easily by hand.

hmmmm.

He said the carb should be richened up slightly and running the timing
to spec should be fine. but seeing it's converted to Petronix
electronic ignition, it should be re-timed.

Once back together, I'm going to do my best to get regular fossil fuel
(no gasahol) and take it from there.

Tim