[Redneck]

I acquired a boat with a 40 hp 4 s year 2000 model Yamah motor. I was told it only has 15-20 hours at most. The person has no reason to lie about this, as we bartered for the boat and I came out extremely well on this trade.

I have had tyhe carb issues twice, first from it sitting up with gas in it, and again when phase seperation happened again in the tank.

How do I know if the timing belt needs changing? From what I have read if it goes there goes the whole motor!

Is there a way to check and know if it is OK?

[rodbolt]

yep
the maint schedule is 1000 hours OR 5 years whichever occures first.
its just to cheap and easy to fix it BEFORE it breaks.
however the F and T 40 motors are clearence engines. if the belt breaks the engine simply stops.

[drewmitch44]

Originally Posted by rodbolt

however the F and T 40 motors are clearence engines. .

Does that mean they are on SALE? Im not sure what you mean by clearance engine. I assumed you ment they are on clearance like marked down in price. Thats a good thing!

[AGENT 37]

Valves get smashed by pistons when the timing belt breaks on interference fit motors. Some motors are designed where there can be no contact between pistons and valves regardless of crank/cam position line-up. I think that clearance and interference fit are being used interchangeably.

[andymach23]

Rodbolt

Is the 1998 F80 also a non-interference engine?

Cheers

Andy

[rodbolt]

the F80 is an interference motor, if the belt lets go odds are high it will take the head with it.

[andymach23]

Thanks Rodbolt,

I just had a look in my service manual for my 2004 F40. Replacing the timing belt looks easy enough. Just line up the timing marks and slip the new belt on.

I will be getting the service manual for the F80 when I get my new boat. Is the timing belt replacement on the F80 (1998) the same deal?

My Yamaha dealer has quoted me 5 hrs labour and 300 pounds ($600) to do the timing belt and water pump (including parts).

I have done a water pump in the past and would tackle a timing belt if it's an easy job.

Just curious.

Andy

[rodbolt]

5 hours?
in five hours,barring any stuck fasteners due to salt water, I could probaly do 3 and be almost done with the 4th.
even a slow tech should be able to change a belt and a water pump in less than 2 hours on the F80 or the F40.
it requires flywheel removle to change the belt on most but its not hard with the correct tools and a pre-read of the service manual to gain some knowledge of what your gonna do.
a quality flywheel holder and a quality harmonic balancer puller make the job a lot easier.