need prop help. new boat to me..

[barhpr]

Hey all. I have a issue and know nothing about figuring out which prop to try. I just brought home a 84 basstracker iii with a 50 mariner on it. The boat has trim tilt, and a trolling motor/battery in the front. I took it out today and was very dissapointed in the performance. The boat as described with a 6 gallon can, me (170lb) and my dad (200lb)... wouldnt plain out untill he got on the bow. Even with him there. Takes a good 30 seconds. It has a 9 3/4 11 pitch alum prop. The best I could get was 23mph wot at 4200 rpm. Seems like I should have better performance on both ends. I also used 5 gallons in the hour we were out. Any advise would help greatly! Thanks.

 

[82rude]

Re: need prop help. new boat to me..

first thing I would check for is a spun hub.if you can eliminate that id think about a 9 p prop for heaver loads.i believe you want 5000 to 55oo rpm ?most likely you have a prop with too much pitch now that I think of it as a spun hub would normally give you rpms but no go!

 

[barhpr]

Re: need prop help. new boat to me..

Thanks for the input. Any ideaa on diameter? This is my first outboard, is 5 gallons in a hour common? If so Im not going half as as far as i had planned.

 

[82rude]

Re: need prop help. new boat to me..

at wot 5 gallons is about right .go to the prop selection section on this site and you will get all your answers and a good deal on a prop.i really like the solas props myself.my boat is basicially flat bottomed and I chose a 4 blade solas amita which has turned out to be great in all respects.make sure your motor and setup is good to go .im assuming all is well and just taking a educated guess at the prop pitch.is the boat heavly loaded?are you using the trim correctly?when you first take off trim in all the way then gradually trim out as your boat gets going .every boat is different but you will get the hang of it quickly.i had a 60 mariner and the 11 p was my power prop but maybe your boat is heavier or ?

 

[steelespike]

Re: need prop help. new boat to me..

A 50 will use about 5 gallons per hour at wot if your struggling it would be higher.I doubt you were at wot all the time.
I think you have more problems than a prop. Based on your info it appears your at about 1300 lbs.
550 for the boat 200 for the motor etc.
If your gear ratio is about 1.85 a 11" prop should deliver at least 5700 rpm and about 30 mph.
At 200 rpm per inch I don't think its possible to add 1300 rpm to get to 5500 rpm by prop selection.
Things to check; Compression,note the condition of the plugs,does the throttle open all the way? Is the motor in excellent tune?
Is it running on all cylinders?Do you trim up for best speed?

 

[barhpr]

Re: need prop help. new boat to me..

ComPression is 140.135.140.135ish.
I trim up until i hear it begin to cavitate, then bump it down twice. The plugs fuel filter and impeller were just changed and look like new. We checked the throttle linkage travel yesterday and it goes all the way it possibly could. I left it to cavitate once yesterday and the rpms came way up so I know not under load the engine can produce more than 4200... I have heard that old basstrackers have foam under the deck that can hold water, i tipped the trailer back till the skag touched for 2 days and didnt get anything. The prop diameter is 9 3/4. The boat does sit way heavy in the water. Maybe I need to scale it and try to deduct the trailer weight. Floating it needs about 9" draft in the rear.

 

[steelespike]

Re: need prop help. new boat to me..

Weigh it,put the boat in the water and weigh the trailer.
Maybe check the timing is set right and advances as it should.
See if tickling the choke helps.
Check the link & sync.

 

[JoshOnt]

Re: need prop help. new boat to me..

Wow my friend you are in the same situation as me, mind letting us know what year?

 

[barhpr]

Re: need prop help. new boat to me..

Mine is a 1984 basstracker with a 1984 mariner. I will put the boat on a scale and then check the trailer. Wont be tonight though Probably tomorrow.

 

[barhpr]

Re: need prop help. new boat to me..

Im sitting exactly 1550 including the trailer

 

[barhpr]

Re: need prop help. new boat to me..

Local boat shop says trigger, switch, or stator. Goes in next week

 

[barhpr]

Re: need prop help. new boat to me..

Problem is fixed! Took it to a local shop, and turns out the timing advance on the motor was hanging up on a plastic ziptie! Cutthe tie off and Im pulling 35mph at 5000 rpm. The tech wouldnt charge me so im dropping off a case of beer this week!

 

[QC]

Re: need prop help. new boat to me..

Excellent!! Good example of how the numbers can work to tell us that low WOT RPM is not necessarily a prop problem.