'96' 75hp Force High Altitude Jetting.

[jpbaker]

Just purchased a pontoon boat w/'96' 75hp Force<br />motor. Trailered it from Atlanta to Denver. Going<br />to replace the impeller plugs ect. My question is<br />do I need to replace the main jet to .088 <br />(recommended @this altitude) or wait till I've <br />tuned it up and see how it runs first? One guy<br />at the local shop said the jet is the last thing<br />to replace, comming from lower to higher altitude,<br />and to try a different prop and adjustments to gain max performance. Any sound advise would be appreciated.. Great form I've already learned alot<br />about these motors.

 

[The Marine Doctor]

Re: '96' 75hp Force High Altitude Jetting.

Changing props n such is alot more expensive than running with the proper Jet in the first place.<br /><br />A 15 pitch might be need to get to the Max RPM range.<br /><br />A 17 pitch might be used once the correct Jet is in place.<br /><br />You decide <br /><br />TMD

 

[jpbaker]

Re: '96' 75hp Force High Altitude Jetting.

Thanks for the info. Will start w/ the jet change<br />and move on from there. Put a new impeller on<br />with the information I got from this forum and<br />took about 1 1/2 hr worked like a champ(manual<br />is on order). Thanks again for the post and I'am<br />sure the ones to come in the future.

 

[9675hpforce]

Re: '96' 75hp Force High Altitude Jetting.

Nope you will need more prop atleast mine does. Running a 17 foot alum Starcraft fishmaster DC loaded around 2000lbs with everything in it. I tried a 11 pitch which was to low,12 was better but still to much rpm now 13 some days perfect others to low or high?

 

[9675hpforce]

Re: '96' 75hp Force High Altitude Jetting.

Switch out the jet its easy there's only one carb. My engine idles bad not sure why but comp tests 109,109,105. She runs better about 1/2 a turn out at the screw lean.

 

[jpbaker]

Re: '96' 75hp Force High Altitude Jetting.

Thanks, will rejet when I get my manual. This has<br />an 11 pitch on it now, once I get it in the water<br />I'll know what to do. I used to own an old tri- hall w/a Johnson 65hp and if I remember it had<br />a 15 pitch on it and ran good. So I surely will have to change the prop also (to a 15 or so like the Doc said) Timing is at 10 degrees, and fuel/air has been adjusted while in the barrel. (Don't like the earmuffs and I drain the water into the yard, plus I get some back pressure which helps simulate being in the lake). Remember, I hauled this up from GA so I have some work to do to get it to peak RPM. I'll post whatever positive changes I get to help others in this forum..

 

[The Marine Doctor]

Re: '96' 75hp Force High Altitude Jetting.

When I mentioned 15 pitch it was just an example.<br /><br />If you are running an 11 now...you might run a 12 or 13 after.<br /><br />15 is a large prop to swing on a pontoon boat.<br /><br />TMD

 

[jpbaker]

Re: '96' 75hp Force High Altitude Jetting.

Thanks advise noted