Sorry so much detail. I have a 1993 21.5 Cuddy
(Dynasty) I put a new 4.3 Mercrusier in it with
new carb, new plugs wire,distributor. manifold(s)
intake and exhaust, alpha one gen II drive.



Boat ran fine for about 20 hours use. I hit a
submerged object(dunnage wood I guess underwater)
at a hard idle it bent the aluminum prop up
moderately but did not spin it. Since the
incident when I try to get the boat on plane it
sputters and dies. I cannot think of what to check
as it will idle/start and rev with no problem when
under lite or no load. Does anyone have any
suggestions on what I should be looking for ?
Thanks Kevan

"Bora Cider" wrote in message
...

Boat ran fine for about 20 hours use. I hit a
submerged object(dunnage wood I guess underwater)
at a hard idle it bent the aluminum prop up
moderately but did not spin it. Since the
incident when I try to get the boat on plane it
sputters and dies. I cannot think of what to check


I wouldn't think that the prop damage is related to your current problem.

The symptoms sound like a typical fuel starvation problem. You said the
motor was new, but what condition was the gas tank in? More important, how
old was the gas in the tank?

About 10 years ago I assumed ownership of my dad's ski boat. The boat had
been sitting for a couple of years, unused and uncovered. The interior was
a disaster, and the last time I had actually seen the boat run it needed a
major tune up so I didn't even try to run the boat before I gave it a good
work over. New upholstery and new carpet. New points, plugs. I pulled the
carburetor off and took it down to a shop that specializes in rebuilding
carburetors and paid them to fix it up.

My mistake was that when I got the carburetor back I attempted to run the
engine with the gas that was still in the tank. It started okay, and ran
good for a few minutes. That was how long it took before the gunk in the
gas tank seriously messed up the carburetor.

The gas had gone bad from sitting for so long. I poured some into a jar and
it was cloudy. It smelled rancid. If you let a sample evaporate it would
leave behind a very fine powder. This powder was fine enough to get through
the fuel filter and clog the passages in the carburetor.

I had to have the carb rebuilt again. I drained the gas tank (it was a real
bitch getting rid of 15 gallons of bad gas). I removed the gas tank and
took it to a radiator shop and had them clean it out for me. I replaced all
the fuel lines and the fuel filter just to make sure that there wasn't any
of that gunk left in the system.

No more fuel problems after that.

If you think that your gas is bad then drain it out and get rid of it. If
it has messed up the carburetor then you will need to have it cleaned out.
You should certainly check the fuel filter, and if it wasn't replaced as
part of this new repower operation you should replace it now. Make sure you
don't have any air leaks between the fuel pump and the tank.

If you still can't find the problem then I would obtain a fuel pressure
gauge (they sometimes double as a vacuum gauge), install a Tee in the fuel
line between the fuel pump and the carburetor and monitor the fuel pressure
while you are experiencing this problem. I would expect the fuel pressure
to be a few PSI.

If you have adequate fuel pressure when the problem occurs then the problem
is either not fuel related or it is in the carburetor itself. Many
carburetors have a fuel screen/filter right at the fuel input so you might
want to check that.

If the fuel pressure falls off then either the fuel pump is bad, the filter
ahead of the pump (if you have one) is clogged, or there is an air leak
between the fuel pump and the tank.

Another test that you can run is a fuel delivery test. Start the boat, let
it idle for a minute. Stop the engine and remove the line between the fuel
pump and the carburetor. Attach a hose to the output of the fuel pump and
direct it to a container that can hold a couple of quarts of gas.

Start the engine and let it run until the gas in the carburetor runs out (I
would expect it to run for 30 seconds or more). Observe the amount of gas
the fuel pump delivered to the container.

I would expect that your engine would burn about 10 gallons an hour when it
is under heavy load. Thus, the fuel pump will need to deliver at least that
much. 10 gallons an hour is one gallon every 6 minutes, or one quart every
1.5 minutes. So, if your engine ran for 90 seconds and it didn't deliver
over a quart then you would have a problem.

Rod

"Bora Cider" wrote in message
...
Sorry so much detail. I have a 1993 21.5 Cuddy
(Dynasty) I put a new 4.3 Mercrusier in it with
new carb, new plugs wire,distributor. manifold(s)
intake and exhaust, alpha one gen II drive.



Boat ran fine for about 20 hours use. I hit a
submerged object(dunnage wood I guess underwater)
at a hard idle it bent the aluminum prop up
moderately but did not spin it. Since the
incident when I try to get the boat on plane it
sputters and dies. I cannot think of what to check
as it will idle/start and rev with no problem when
under lite or no load. Does anyone have any
suggestions on what I should be looking for ?
Thanks Kevan

Check the timing. the abrupt stop may have cracked the rotor.

"Calif Bill" wrote in message thlink.net...
"Bora Cider" wrote in message
...
Sorry so much detail. I have a 1993 21.5 Cuddy
(Dynasty) I put a new 4.3 Mercrusier in it with
new carb, new plugs wire,distributor. manifold(s)
intake and exhaust, alpha one gen II drive.



Boat ran fine for about 20 hours use. I hit a
submerged object(dunnage wood I guess underwater)
at a hard idle it bent the aluminum prop up
moderately but did not spin it. Since the
incident when I try to get the boat on plane it
sputters and dies.

Check the timing. the abrupt stop may have cracked the rotor.

Wouldn't it be just as easy, and more prudent to just check the rotor, then?

Strange problem if it is related to the drive. Hope its not a coincidental
problem that surfaced at the same time.

You mentioned light or no load. Could the drive be the source of the high
loading?

Check if the prop shaft spins freely. With the prop in neutral gear, give
it a spin.
With boat on trailer out of water, run it in gear. Look for eccentricity
and listen for funny noises from drive.
Check the oil to be sure there's no damage allow water ingress.

Hope you find nothing. Check the the acceleration jets in the carb.

Ta PS

"Bora Cider" wrote in message
...
Sorry so much detail. I have a 1993 21.5 Cuddy
(Dynasty) I put a new 4.3 Mercrusier in it with
new carb, new plugs wire,distributor. manifold(s)
intake and exhaust, alpha one gen II drive.



Boat ran fine for about 20 hours use. I hit a
submerged object(dunnage wood I guess underwater)
at a hard idle it bent the aluminum prop up
moderately but did not spin it. Since the
incident when I try to get the boat on plane it
sputters and dies. I cannot think of what to check
as it will idle/start and rev with no problem when
under lite or no load. Does anyone have any
suggestions on what I should be looking for ?
Thanks Kevan