Need a better prop for Johnson 150

[BelewsBoater]

99 Johnson 150 HP with 13.5x23 Bass Renegade 4 blade on 17' Sprint bass boat only get 4,300 to 4,400 rpm at WOT. If I purchase a Raker with same pitch will I get a better rpm and increase in speed? The manual says the mid range for this motor should be at 4,500 to 5,500 rpm and I'm getting lower than recommended. What size and model prop do you recommend I try? Thanks.

 

[Dhadley]

Re: Need a better prop for Johnson 150

For the best performance with that motor - and longest life - you'll actually be looking for 5600-5800. 6000 is not out of the question but if you're using ethanol it may be hard to get. Anyway, the 13.5" diameter prop doesn't work well with a V6 style gearcase. Therefore it's really hard to compare a Renegade Bass to a Raker. Completely different props. The Renegade Bass has lots of slip, the Raker may not - depends on which version of Raker you're talling about.

To give a better recomendation on a prop we'd need to know more about your set up. What kind of jackplate do you have?

 

[BelewsBoater]

Re: Need a better prop for Johnson 150

Anyway, the 13.5" diameter prop doesn't work well with a V6 style gearcase.

To give a better recomendation on a prop we'd need to know more about your set up. What kind of jackplate do you have?

What diameter do you suggest I should get? The 13.5" prop was already on it when I bought the boat (my first boat) in June and have been driving it since. At WOT it kinda feel slow like 40's mph. Had the compression test done at marina and it is good. I don't know if it is because I had the motor trimmed way down instead of out or because of the diameter or both? The boat doesn't include jackplate.

 

[Dhadley]

Re: Need a better prop for Johnson 150

It'd be a safe bet that without a jackplate we're not going to get all the performance out of that hull that it's capable of. That doesn't mean it can't get better than it is. But we have a decision to make. If we're looking for max performance then we should consider a jackplate. Generally speaking, there's no need to buy a prop with technology we can't use. If we're not adding a jackplate we can use props that don't have as much technology, no sense paying for something we're not going to use.

There's also no sense to buy a prop now if we plan to add a jackplate at some point. Basically the point is that this is the time to make a plan. Once that decision has been made we can go forward. The props that work the best on that hull will be in the 14 1/4 to 14 3/4" range.

 

[BelewsBoater]

Re: Need a better prop for Johnson 150

I read a post through Google that it is not a good idea to add a jackplate on less than 18' boats and less than 150 HP. I need to do some more research on that before adding one or not. Appreciate the feedback, Dhadley.

 

[junior1113]

Re: Need a better prop for Johnson 150

id put a jackplate on it. even a manual would help. some props are designed to ride closer to the surface than others. the only way to find optimum height for a particular prop is to change engine hieght. 2 props will have different sweet spots. engine hieght means so much for best performance.you will blow that motor if keep running it at 4500 wot. i'd run that motor 5600-6000. they last longer. my 2 cents

 

[Dhadley]

Re: Need a better prop for Johnson 150

Keep in mind that not all 17' boats are created equal. Just like all props of a given pitch are not created equal. It's true that set back, even 4", may hurt some boats like the 17' Mavericks. However, a 17' Hydrostream needs 5 or 6" of setback to perform correctly. I had a 15' Allison that ran pretty darn good with 6" of setback and a 120hp V4. So much for the Google theory.

Your boat may not need the typical 5-6" of setback but it'll probably do well with 3". If it were mine I'd look into the Bob's convertable manual jackplate. Flip it inside so the setback is at about 3". One very good thing in your favor is that your motor is one of the lightest V6s around.

 

[BelewsBoater]

Re: Need a better prop for Johnson 150

Took the boat out today. Once it was on plane I trimmed the engine out some and noticed the RPM and speed increase. At WOT it reached 62-63 mph via GPS at about 5600-5800 RPM. Didn't change anything except trimming out. Flies like a dream.

you will blow that motor if keep running it at 4500 wot. i'd run that motor 5600-6000. they last longer. my 2 cents

Glad I listened because if I haven't it would have been screwed already if I continued to have it trimmed in all the way like I've done since June! Obviously is what caused low RPM.

Thanks to you two.

 

[junior1113]

Re: Need a better prop for Johnson 150

cheap fix. trim up untill slight blow out then trim down a little. uneeded drag kills engines. it will also have better mpg now.