150hp

[proanglerwannabe]

I have a 1996 force 120. I am looking for a 1996 or above 150. Tryin to stick with a force or merc. I dont want to have to change the controls and cables. please let me know if ya'll have any leads.

 

[pnwboat]

Re: 150hp

Last year for the Force 150 HP motor was 1994.

 

[proanglerwannabe]

Re: 150hp

Ok well thanks for the info. Are there any good 150s that I can rely on if taken care of? the earlier years are the ones I worry about. Lots of bad reps. But let me know. thanks Again

 

[pnwboat]

Re: 150hp

They're all mechanically reliable if maintained properly, but if I had to chose one year over the other, I would lean towards 1991 and later that used the Mercury Thunderbolt ignition system over the Prestolite ignition system. Not due to reliability but easier to trouble-shoot....but that's just me.

 

[SkiDad]

Re: 150hp

Why not stick with 120 and have spare parts. I can't imagine you will gain much with the 150.

 

[SweeperForce]

Re: 150hp

I have a 150 and love it. Only had a few problems but what do you expect for a 24 year old motor. They do suck down gas. At 3/4 throttle you might get about 3 hours at best on a tank of gas. I hit 43mph last year with a alum prop. This year I'm going SS and with it properly trimming I'm hoping for 45-46. Any other questions feel free to ask.

Tom

 

[proanglerwannabe]

Re: 150hp

Thanks tom. I got up to around 45 with a loded boat family installed and all. HAHA I have not taken all my gear out yet for an empty run but I plan to this summer. It runs great but i was wondering what another 30 hp will do. I am looking for a 21p prop to throw on her to see if that will improve my get up and go. The hole shot aint bad top speed aint bad either fully loaded. I would like to find a 150 to tinker with and rebuild. I too had a 17p aluminum on this motor. Funny story, I could only afford this motor at the time. But it was a 25" shaft. The boat had 6" setback jackplate and figured it would work. Well I do river fishing and this being my first large boat, large HP I basically drug the skeg and prop through mud. Didnt hurt anything mechanically but chewed on the prop blades a little. My fix, I took it all apart, did some research, took out the 5" extention block in the housing, cut the drive shaft, shift shaft and water tube. Had them welded by a very reliable professional. Reinstalled everything. Repainted the Lower Unit. Worked like a charm. That was the smoking gun. It runs great, and performs outstanding. This year I am gonna add a hydrofoil, and 21"p prop to see wha she will do. I am gonna buy a 21p alum first. alot cheaper than ss. I appreciate the knowledge. I dont have any pics with me but its a 1986 Ranger 373V commanche BMC. works great and I love it.

 

[Frank Acampora]

Re: 150hp



Typically, you need to quadruple horsepower to double speed. Thus. Stepping up from a 90 to a 125 on this boat only increased speed from 55 to 60.

HOWEVER: The 150 has about 25 more cubic inches displacement and more torque due to the extra cylinder. Therefore stepping up from 120 may possibly give you more than 5 MPH. There are a lot of variables though and what is expected may not necessarily be what is acheived.

My cuddy has a Chrysler 140 and it is slated to be replaced with a 150. I an hoping for significantly more than 5 MPH gained.

 

[SweeperForce]

Re: 150hp

Becareful not to lower your pitch to much. The lower the pitch the higher your rpms. My max is 5500rpm at WOT. With a 19 pitch alum prop I get 43mph with just me onboard, as I stated above. I would choose a prop that puts you in that sweet spot (5300-5500rpms) Then check you speed. Over-revving from a lower pitch is just as bad as underpowering from a larger pitch. Also a smaller boat will go faster with a smaller motor.

 

[jerryjerry05]

Re: 150hp

The gas mielage is gonna go way down with the wrong prop.
You need to figure out the wot rpm's then prop accordingly.
I tried a different pitch on my twins.
From a 17 to a 19 Got about 2-3 mph more and used about 20% more gas!!!

 

[proanglerwannabe]

Re: 150hp

Thanks for the info. Looks good I hope it works out. I will keep looking around. I plan to get a 21p first of course. wish me luck

 

[proanglerwannabe]

Re: 150hp

I have a 17p now I plan to go to a 21p next. That will drop my rpms down to a more managable level. I could run then at 6000 easy because I shortened the drive shaft. Thus raising the operating rpms but it still isnt good. so mercury sugested a 21p to get the rpms down. I for now just just away from wot. thanks for the info

 

[proanglerwannabe]

Re: 150hp

Oh yes for sure. I will weigh the options. If I only get 3 or 4 more mph And an increase in gas usage i will op out for the 17p but I want to try it to see if there will be a gain i can be happy with. thanks for the info

 

[Frank Acampora]

Re: 150hp

Max RPM has nothing to do with the drive shaft length! Indeed, the 20 inch and 25 inch engines of the same horsepower have the same operating range of 4500-5500 with rated horsepower developed at 5000 RPM. In fact, since your shaft has been shortened and welded, if anything I would downrate the maximum RPM and horsepower it would take, experienced welder or not!

Since these engines don't have valves to "float" They can be run well above rated RPM up until the point where the flywheel would explode or they would throw a rod.

The RPM range is determined by cylinder port timing. Go past maximum quoted and peak horsepower starst to drop. The goal of prop selection is to maximise pitch AT the maximum rated RPM-5500. You want to select a pitch that will let the engine operate at 5500 at WOT! This will yeild the best top speed and fuel economy (in most cases). Top speed is not only a function of horsepower but dependent also upon hull design, total weight being moved, gear ratio, and prop material and design.