help with prop selection please am going crazy reading

[robertrojo]

Well this is what I have 1988 proline. 20ft walk around with mercruiser. V6 4.3l and OMC
sterndeive am running a 15x 17 prop wot is 3700 and 27mph full speed . I think am slow and I already did a havy tune up

I want to reach OEM wot that is 4400 and a desent full speed like 35mph

 

[WILSONS88]

Re: help with prop selection please am going crazy reading

Here try this.

http://www.mercurymarine.com/propellers/prop-selector/#

 

[robertrojo]

Re: help with prop selection please am going crazy reading

Result was 15x15

 

[WILSONS88]

Re: help with prop selection please am going crazy reading

I think Iboats has a prop selector also.

 

[steelespike]

Re: help with prop selection please am going crazy reading

I think you have more than a prop selection issue.You should prop for wot rpm of 4800.
So your 1100 rpm off and it appears the tach is accurate.It would take about a 12" pitch
to reach about 4800 rpm.Thats a prop for hard to push boats like a pontoon.
I think your 17 should be over 40mph and about max rpm.
Is the prop n excellent shape?Is the bottom clean and smooth?
Does the carb open all the way?
Is the timing right and advancing as it should?
Does the boat respond when you trim up?
Sometimes older boats have absorbed water in the foam under the floor,this can contribute to slow hole shot and reduced speed though would likely only partially to your poor performance.

 

[SparkieBoat]

Re: help with prop selection please am going crazy reading

ditto what steel said

 

[robertrojo]

Re: help with prop selection please am going crazy reading

Please if u can call me 954 4044587 I dont. know too much about boats! Please!!

 

[oops!]

Re: help with prop selection please am going crazy reading

Sometimes older boats have absorbed water in the foam under the floor,this can contribute to slow hole shot and reduced speed though would likely only partially to your poor performance.

after the engine issues and the wot is reached.....i would be looking at the hull......weighing the boat on scales is a good indicator for waterlogging.

Please if u can call me 954 4044587 I dont. know too much about boats! Please!!

the reason for the forums is so all can learn......hang in there...you are in good hands.

btw....if you want to learn about boats......this is boat university...just read

 

[robertrojo]

Re: help with prop selection please am going crazy reading

First it does get out of the hole extremely quick a nice torque! Second my girldfriend told me that at 1500 rpm it creates kind of big waves! The bottom and Hull I think for a 88 it is brand new! I don't know how to do the trim up thing how did u do that

 

[robertrojo]

Re: help with prop selection please am going crazy reading

Yes it does trim up the top of the Carb I think it doesn't work but the butterfly they do open all the way I know now what trim is it does it right! !

 

[NESAR]

Re: help with prop selection please am going crazy reading

I just use one that works.

 

[SparkieBoat]

Re: help with prop selection please am going crazy reading

you need to get someone who knows about outboards to show you how to run your boat..and maybe take the motor to a mechanic for a check-up. it is hard to explain everything to you in a forum. you just seem to lack even basic knowledge of boating and for your safety you really should get someone to go over how to operate a boat. there may even be boating classes near you, but if you see a boat in a neighbors yard go introduce yourself, most boaters would be willing to help you out.