Am I damaging my engine?

[markrolf]

Re: Am I damaging my engine?

Do you attribute the problems
to low rpms?

10 dollars a gallon? Gulp:%

6 Cyl to 4 cyl hum

4.3 to 3.0
that is a reduction.
You will still have to gear and prop to
run a respectable rpm.
I don't know if there available and (usually
reduce not increase)or whether you can fab
them but it is different size pulleys.
There are under size pulleys for some performance
engines that will reduce horsepower loss and
reduce rpms that pumps, alternators, ect. spin
The same technique could be used to increase
rpms of pumps, pulleys ect.
I am trying to state that an engine swap
by itself will not fix the idle speed issues your
having.
I feel you need to get the rpms up on whatever
motor you go with.
how much is Diesel going for?

Thing is, a diesel engine (new) cannot be had for much less than £10k ($20,000), so that's not really an option.

The boat is a Larson 250 San Marino, which are very rare in the Uk.

We average about 40 hours a year, and unfortunately we don't have the luxury of lakes on the inland rivers! You guys have it so much better!!!

We've had Volvo out and paid them a stupid amount of money to 'fix' it, which they didn't do. I don't know, we've lost faith in it and I think the best way forward is to repower.

Thanks for the advise and comments so far!!

 

[calwldlif]

Re: Am I damaging my engine?

Mark
25 foot boat with 4.3 idling
at 7 mph
You have a big prop!
21 in?
get a 15 inch

Do you feel your present motor is
to far gone?
As stated by some knowledgable people
a smaller cubic inch motor
isn't going to save enough to warrant
a change.
I don't know what your volvo guys
did or recommended but
a repower aint cheap.
Are you willing to reprop and work with people
here to get ya going?
There is a solution, lets find it

 

[markrolf]

Re: Am I damaging my engine?

Mark
25 foot boat with 4.3 idling
at 7 mph
You have a big prop!
21 in?
get a 15 inch

Do you feel your present motor is
to far gone?
As stated by some knowledgable people
a smaller cubic inch motor
isn't going to save enough to warrant
a change.
I don't know what your volvo guys
did or recommended but
a repower aint cheap.
Are you willing to reprop and work with people
here to get ya going?
There is a solution, lets find it

The figures you quote are spot on, we have a duo-prop which, IIRC, is around 12-13 inches. It's not that big really. We either use around 1000-1100 rpm to achieve 5.5 knots, 7 knots is around 1200 rpm.

Just don't know what to do?

 

[calwldlif]

Re: Am I damaging my engine?

DuoProp.....kewl (if you want performance)
the bottom of drive can be swapped with
a single screw(sell your duo and make money +a new
single)
Then you could find a 13pitch or so and still
have money left.............

 

[180shabah]

Re: Am I damaging my engine?

Does anybody make the diesel outboards for us here in the US?