120hp '95 Johnson suddenly running at half speed
 

Yesterday evening I took my boat out and ran it about 1 hour straight
at full throttle, stopped at a restaurant for dinner for an hour, and
then ran it for 20 minutes straight until it suddenly started slowing
down on its own accord. I assumed I was somehow running out of gas from
the way the speed tapered down but that was not the case. For the rest
of the ride home, if i floored the engine, it would pull up like it was
trying to go full speed and plane out, but taper back down quickly. The
flywheel felt very hot when I touched it. Any ideas what could cause
this? Did the engine just overheat and this was its way of telling me
to slow down? (water was 86 degrees, air was like 84 probably). It's
done this before occasionally, and then run perfectly the next time I
took her out.

In addition, the engine sometimes slips in and out of gear. Often when
the throttle is in neutral, the 'clutch' lever (for lack of knowing the
right term) doesnt go all the way back and the prop will spin if the
engine is on. If the engine is off, the prop is locked in place and
wont spin freely. I get around this problem by often lifting the hood,
pushing the lever all the way back to get the boat into neutral. Is
this possibly stealing horsepower from my motor?

Sorry for the lack of technical terms, this boats a bit of a learning
experience for me.

120hp '95 Johnson suddenly running at half speed
 

On 3 Aug 2006 12:44:48 -0700, "OldReliable" wrote:

Yesterday evening I took my boat out and ran it about 1 hour straight
at full throttle, stopped at a restaurant for dinner for an hour, and
then ran it for 20 minutes straight until it suddenly started slowing
down on its own accord. I assumed I was somehow running out of gas from
the way the speed tapered down but that was not the case. For the rest
of the ride home, if i floored the engine, it would pull up like it was
trying to go full speed and plane out, but taper back down quickly. The
flywheel felt very hot when I touched it. Any ideas what could cause
this? Did the engine just overheat and this was its way of telling me
to slow down? (water was 86 degrees, air was like 84 probably). It's
done this before occasionally, and then run perfectly the next time I
took her out.

In addition, the engine sometimes slips in and out of gear. Often when
the throttle is in neutral, the 'clutch' lever (for lack of knowing the
right term) doesnt go all the way back and the prop will spin if the
engine is on. If the engine is off, the prop is locked in place and
wont spin freely. I get around this problem by often lifting the hood,
pushing the lever all the way back to get the boat into neutral. Is
this possibly stealing horsepower from my motor?

Sorry for the lack of technical terms, this boats a bit of a learning
experience for me.

I don't know what your problem is, but I'd never run my boat at full
throttle for longer than a few minutes. My normal cruising speed is at
about two-thirds of full throttle.

Good luck!
--
******************************************
***** Have a Spectacular Day! *****
******************************************

John

120hp '95 Johnson suddenly running at half speed
 

If an outboard is given good fuel and oil, is propped correctly, and
maintained properly, there is no problem running it a full throttle. The
problem, the average person does not follow this.

If you were overheating to the point where the engine would be reducing
speed, the warning horn would sound and the Johnson would go into SLOW.
Speed limit overheat warning. And you would know it because it would not
run over 2000 rpm's and would shake like hell. Unless your warning system
is non functional. Checking this occasionally is part of normal
maintenance.

How do you know it's not starving for fuel?

If this is all greek to you, then you need to seek some professional help
with this motor.

Ron

"OldReliable" wrote in message
ups.com...
Yesterday evening I took my boat out and ran it about 1 hour straight
at full throttle, stopped at a restaurant for dinner for an hour, and
then ran it for 20 minutes straight until it suddenly started slowing
down on its own accord. I assumed I was somehow running out of gas from
the way the speed tapered down but that was not the case. For the rest
of the ride home, if i floored the engine, it would pull up like it was
trying to go full speed and plane out, but taper back down quickly. The
flywheel felt very hot when I touched it. Any ideas what could cause
this? Did the engine just overheat and this was its way of telling me
to slow down? (water was 86 degrees, air was like 84 probably). It's
done this before occasionally, and then run perfectly the next time I
took her out.

In addition, the engine sometimes slips in and out of gear. Often when
the throttle is in neutral, the 'clutch' lever (for lack of knowing the
right term) doesnt go all the way back and the prop will spin if the
engine is on. If the engine is off, the prop is locked in place and
wont spin freely. I get around this problem by often lifting the hood,
pushing the lever all the way back to get the boat into neutral. Is
this possibly stealing horsepower from my motor?

Sorry for the lack of technical terms, this boats a bit of a learning
experience for me.

120hp '95 Johnson suddenly running at half speed
 

I follow you Ron. I've got a general knowledge of how the engine works
and the components, just don't know the terms. Although I'll admit I
had no clue there was a warning system for my engine. Sadly the tach
doesn't work on my boat, so i'm at a loss when it comes to the actual
RPMs its putting out. It's not shaking or anything, and actually i
would not be suprised if it was due to a vacuum developing in the fuel
line somewhere which was impeding the flow. I'll double check the
filters too.

When I say full throttle I guess i should say that I went about 90%
throttle, it's a heavy boat and when you've 4 people on it, it takes
that much to stay on plane.

Just got this engine back in April, so I havent done any preventative
maintenance just yet, although I have tinkered with a few random issues
and feel satisfied it's running well normally.

I guess my main concern is whether or not the 'clutch' issue i talked
about earlier is to blame (and how to fix it). Checking the fuel line
is pretty easy, so that will be my first move.

Ron Knapik wrote:
If an outboard is given good fuel and oil, is propped correctly, and
maintained properly, there is no problem running it a full throttle. The
problem, the average person does not follow this.

If you were overheating to the point where the engine would be reducing
speed, the warning horn would sound and the Johnson would go into SLOW.
Speed limit overheat warning. And you would know it because it would not
run over 2000 rpm's and would shake like hell. Unless your warning system
is non functional. Checking this occasionally is part of normal
maintenance.

How do you know it's not starving for fuel?

If this is all greek to you, then you need to seek some professional help
with this motor.

Ron

"OldReliable" wrote in message
ups.com...
Yesterday evening I took my boat out and ran it about 1 hour straight
at full throttle, stopped at a restaurant for dinner for an hour, and
then ran it for 20 minutes straight until it suddenly started slowing
down on its own accord. I assumed I was somehow running out of gas from
the way the speed tapered down but that was not the case. For the rest
of the ride home, if i floored the engine, it would pull up like it was
trying to go full speed and plane out, but taper back down quickly. The
flywheel felt very hot when I touched it. Any ideas what could cause
this? Did the engine just overheat and this was its way of telling me
to slow down? (water was 86 degrees, air was like 84 probably). It's
done this before occasionally, and then run perfectly the next time I
took her out.

In addition, the engine sometimes slips in and out of gear. Often when
the throttle is in neutral, the 'clutch' lever (for lack of knowing the
right term) doesnt go all the way back and the prop will spin if the
engine is on. If the engine is off, the prop is locked in place and
wont spin freely. I get around this problem by often lifting the hood,
pushing the lever all the way back to get the boat into neutral. Is
this possibly stealing horsepower from my motor?

Sorry for the lack of technical terms, this boats a bit of a learning
experience for me.