Motor problem! Please help

[wolfe99]

Ok
I have a 1988 21' Bayliner Trophy with a 4.3L in it. For some reason it ran good the first time I took it out. Now everytime I go out it gets slower and slower. Used to run 5000 rpm at around 31MPH with a 17 pich. Now I get maybe 4300 rpm and the boat wont plane out even with the trim tabs. Is it a tune up problem you think?? Its been along time I think since this boat has had one done. Motor seems to run fine at low speeds, but at full throttle its not.

 

[gcboat]

Re: Motor problem! Please help

Definately start with a complete tune up. Then move on to your fuel filters. If the ole' gal has sat awhile with old fuel then the chances of it be contaminated are really good, especially if the tank was not completely full.
If you don't have one you should buy a cartridge type fuel filter, such as Racor, etc. They mount on the bulkhead between the motor and fuel tank. Also take a close look at your carb, could be full of junk or possibly an air leak. Coil could be getting tired, etc, etc. There are three things a motor needs to run: fuel, air and an ignition source. You have those, now need to find out why they just aren't working well together.

 

[WAVENBYE2]

Re: Motor problem! Please help

5000 rpm's is way too high, you should be using a 20 or 21 pitch prop. at 36-3800rpm's I get 44-50mph. your normal should be 4200-4800 tops. Yes your definitely due for a complete tune-up,oil change etc...

 

[WAVENBYE2]

Re: Motor problem! Please help

My boat is the fastest on the lake so far... I fly past em holding their dipsticks in there hand, Hooty or what ever that is you do on your free time, give what, you don't know a damn thing about boats do ya, you got the dumb *** thing down though, Good job buddy, we are proud that all your effort has payed out

 

[WAVENBYE2]

Re: Motor problem! Please help

TESTING , TESTINGc. If clearance exceeds specifications, it will be
necessary to ream valve guides for oversized
valves, as outlined under ?Valve Guide Bore
Repair.?
72336
b
c
a
- Valve Stem
- Dial Indicator
- Valve Guide
2. Ream valve guide bores, as shown.
72886
3. Remove the sharp corner created by reamer at
top of valve guide.
Valve Springs - Checking Tension
Using valve spring tester, as shown, check valve
spring tension with dampers removed. Refer to
?Specifications.?