Prop problem?

[Kwaynem]

I have a 94' 40hp mecuury tracker on a 17' bass tracker it won't get up on plane just takes off slowly. I was out today with the wife took off and when we got to top speed I was running 4100 rpm with a 22 mph wind at our back on the way back facing the wind 3200 rpm the prop is 13 pitch on it now what angle should the motor be trimmed all the way down? Do I need a different pitch than 13?

 

[jimmbo]

How long have you owned this unit? Did its performance take a turn for the worse? Have you checked to see if it running on all 4 cylinders? Your engine has a WOT range of 5000 - 5500 rpm. I suspect you have a dead cylinder, or one of the carbs is flooding or starving two cylinders

 

[Bondo]

what angle should the motor be trimmed all the way down?

Ayuh,....... Generally speakin',... We start out trimmed all the way down, 'n as the hull rises outa the water, ya trim up to get the bow up, for a clean attitude for plannin',...

 

[Sea Rider]

Poor rpm performance was when boat was light, medium light or heavily loaded ?

Wot tests must be done on flat calm, no wind water cond.

Check if engine sits at the sweet transom height.

If engine is doing its homework right, could have a prop on its way to become spun, check.

If prop and OB are found ok, seems combo is too heavy, will need 2-3 less prop pitch to pull wot revs up.

Happy Boating

 

[Kwaynem]

How long have you owned this unit? Did its performance take a turn for the worse? Have you checked to see if it running on all 4 cylinders? Your engine has a WOT range of 5000 - 5500 rpm. I suspect you have a dead cylinder, or one of the carbs is flooding or starving two cylinders

I have owned it for about a year I bought it without the chance to test drive but was told bring it back within 30 days if I find something wrong I took it out and didn't get to try it be side of an electrical problem I took it back and got it fixed then because of long hours at work haven't got to go back out till yesterday 30 days long gone but work pays the bills motor is trimmed all the way down

 

[Bondo]

motor is trimmed all the way down

Ayuh,.... Is it power trim,..??

It could well be plowin', causin' yer low speeds, 'n rpms,...
Once the hull pops up onto plane, hit the trim Up in short bursts, 'n see if it takes off, 'n Runs,...
If ya trim to high, the prop will blow-out, 'n it'll drop off plane,...
If so, trim down, 'n start off again, once on plane, trimmin' up to a nice balanced attitude,...

 

[Kwaynem]

It won't jump up period it's like you have alot of weight on the front end and it never gets up just takes off slowly I have tried the trim like normal it didn't work either

 

[jimmbo]

Are the carbs opening fully? Timing set correctly. Is the cable to the control box adjusted correctly? Compression Test? Spark at all plugs? Are the plugs fouled? Are both carbs getting gas?

 

[Kwaynem]

Are the carbs opening fully? Timing set correctly. Is the cable to the control box adjusted correctly? Compression Test? Spark at all plugs? Are the plugs fouled? Are both carbs getting gas?

Just put new plugs in the smelled like gas compression was 62 to 65 on all four cylinders how do I check to see if linkage is operating correctly? It seem like it is to me I'm a one man band so it's hard to watch I'll get help if I know what to look for

 

[jimmbo]

62 to 65? Psi or? That sounds really low. How are you checking the compression? All plugs out, fully charged battery? Cranking the engine until the reading doesn't increase?

 

[Kwaynem]

62 to 65? Psi or? That sounds really low. How are you checking the compression? All plugs out, fully charged battery? Cranking the engine until the reading doesn't increase?

Fully charged battery all plugs out engine cold

 

[David Young]

Looks like you bought a boat with the motor needing a rebuild

 

[Kwaynem]

Looks like you bought a boat with the motor needing a rebuild

Figures

 

[David Young]

Figures

Don't give up hope yet. Try another compression gauge, I have read ' some don't gauge right'. You can rent them for free from most auto parts stores. There is still hope

 

[Kwaynem]

OK thanks David

 

[jimmbo]

your gauge has to be reading low

 

[Kwaynem]

your gauge has to be reading low

That's what I'm hoping I'm looking for another one right now

 

[Kwaynem]

OK got a different guage. Compression is 120-130-130- 120

 

[jimmbo]

Those are much better. Now you need to verify thing like max timing advance, carbs not gummed up, carb to timing sync and if carbs are opening fully. If those are to spec and engine is still low on rpm, then a prop with less pitch will be needed

 

[Kwaynem]

Jimmbo I can have someone put the throttle all the way down and it's like the linkage on the motor moves slower than than the throttle like it keeps moving after he quits moving the throttle