89' Force 125hp, Max Rec. RPM range?

[MikDee]

Now that I finally have a working tach, could someone please tell me the maximum recommended safe RPM range?

 

[Scaaty]

Re: 89' Force 125hp, Max Rec. RPM range?

Mines great at 5400

 

[MikDee]

Re: 89' Force 125hp, Max Rec. RPM range?

Mines great at 5400

Thanks, but I meant what the book calls for to keep it all together.

 

[baxtr]

Re: 89' Force 125hp, Max Rec. RPM range?

5000 to 5500rpm right out of the manual.

 

[MikDee]

Re: 89' Force 125hp, Max Rec. RPM range?

Many thanks baxtr, Now I know what to shoot for, I'm getting 4,500 on what I believe to be a 13X19" Michigan prop, not too shabby then. Actually I think I have narrowed my issue down to the motor appears to be loading up at the critical times when I slow down from a run, or when I'm trying to shift, I also noticed a slow response out of the hole, and strong smell of gas ocassionally. If I can find out what's causing this I think my rpm's may even come up into range, and I may finally be good to go.

 

[baxtr]

Re: 89' Force 125hp, Max Rec. RPM range?

should try to get it as close to max rpm, better for the motor I have exact boat and motor, mine has a 13 1/4 X 17 prop

 

[ski_king]

Re: 89' Force 125hp, Max Rec. RPM range?

How fast are you going at max RPM?

Per the factory manual, Recommneded Operating Range: 4500 - 5500 RPM.

 

[bowhuntrrl]

Re: 89' Force 125hp, Max Rec. RPM range?

You need to drop to a 17 pitch to get the motor into its "power band". Try to aim for 5200-5400 rpm.

 

[MikDee]

Re: 89' Force 125hp, Max Rec. RPM range?

How fast are you going at max RPM?

Per the factory manual, Recommneded Operating Range: 4500 - 5500 RPM.

40mph max when fully trimmed out, approx 4500-4600rpm

Actually what I meant was the motor is loading up, not because of the prop, but once I get that problem solved, I'll look for a 17" pitch prop, if need be.

 

[lakelover68]

Re: 89' Force 125hp, Max Rec. RPM range?

I had been using a 19 and running around 5000 Rpm.........fully trimmed at about 40 -43 mph............unsure how reliable water speedo is...........then tried a 21 and a 23 prop...........RPM dropped significantly as I was pushing too much water for motor............all in all 17-19 props are ideal !!!!.....for me...........hope this helps

Hmmm.............maybe this explains my head gasket.........pushing the motor to hard something has to give..............................I wonder.........Maybe can't blame force just blame me !!!!!!!!

 

[MikDee]

Re: 89' Force 125hp, Max Rec. RPM range?

I have a lead on a 16" pitch Stainless prop at a good price, if it's still available? (an odd number I know), but I figure I might gain 2-300 rpm, and unload the motor some all around, while providing less flex slippage. Looking for opinions?

 

[Scaaty]

Re: 89' Force 125hp, Max Rec. RPM range?

Thanks, but I meant what the book calls for to keep it all together.

I have pretty much the same boat, and a 19p has me close to 5400 on a good day, so ya might want to look a little at the motor first..? 4500 awful low..

 

[Nate3172]

Re: 89' Force 125hp, Max Rec. RPM range?

In response to your runability issues for "loading up" and running rich at low rpm's, I suggest looking into the fuel recirculation system. A failure in this department can cause some of those symptoms. Float levels set too high can also do the same. If they are just a smidge too high than fuel spills out into the carb at lower rpm's but when the rpm's incease and the load on the engine increases, the engine uses more fuel and it starts to clean itself out.

 

[MikDee]

Re: 89' Force 125hp, Max Rec. RPM range?

I have pretty much the same boat, and a 19p has me close to 5400 on a good day, so ya might want to look a little at the motor first..? 4500 awful low..

5400! Geez!, What's your compression numbers 150lbs? Mine are only 120lbs all around.

I've been thru the carbs everythings been set to specs, all jets blown clean, & pristine, carb mixture 1 turn out (best running), checked & reset the timing, reset the link, & synch, put new Champion plugs in, fuel filter screen clean, hose bulb always firm, fuel pump looks good, but the diaphram is slightly stretched (although still a soft rubbery condition) and no holes, or tears. I am presently cleaning out the piddle valves, & screens, not sure how they work though? are they supposed to be "one way" valves?

 

[Nate3172]

Re: 89' Force 125hp, Max Rec. RPM range?

yes, they are one way valves. To check those, depending on how your's is set up, you can simply remove the hose, or hoses, where they attach at the intake side of the motor and blow back through them. If you can blow back through, than the check, or reed if equipped, is faulty and should be replaced.

 

[Scaaty]

Re: 89' Force 125hp, Max Rec. RPM range?

5400! Geez!, What's your compression numbers 150lbs? Mine are only 120lbs all around.

I've been thru the carbs everythings been set to specs, all jets blown clean, & pristine, carb mixture 1 turn out (best running), checked & reset the timing, reset the link, & synch, put new Champion plugs in, fuel filter screen clean, hose bulb always firm, fuel pump looks good, but the diaphram is slightly stretched (although still a soft rubbery condition) and no holes, or tears. I am presently cleaning out the piddle valves, & screens, not sure how they work though? are they supposed to be "one way" valves?

Well after trashing the Stator + one P Pack, snapping a Driveshaft, misc other Force probs, guess I'm kinda lucky. Have 3 other boats, and it knows ya **** me off, its parted out on Ebay...ya gotta be firm!

 

[MikDee]

Re: 89' Force 125hp, Max Rec. RPM range?

Alright, I finished cleaning the piddle drains, & screens the best I could with Deep Creep, & Carb cleaner (I managed to get new gaskets, but no luck getting the screens), they came out pretty good though. Then managed to get to the lake today to test it out. I was pretty happy when it started, & I shifted into reverse to get off the trailer, and it didn't stall! I was then able to maneuver over to the dock, without stalling, and wait for my wife. It definitely was running better, but it was short lived, as I pulled away from the dock it started stalling again, sure seemed like it was loading up some still, but it was maybe 50% better at not stalling. I continued out into the lake, and when I hit it, it actually sounded, & felt healthier, but I'm still not out of the woods yet, I could still only get 4600 rpm's WOT fully trimmed out, the speedo was just kissing 40mph, basically the same as it has been from the beginning, even tho the motor seemed stronger. I'm running out of things to try next, and it's still stalling some?

 

[gregmsr]

Re: 89' Force 125hp, Max Rec. RPM range?

Is idle set to spec? Turned my idle up a little and, no stalling at dock anymore.

 

[MikDee]

Re: 89' Force 125hp, Max Rec. RPM range?

Thanks greg, but once I got on the lake I raised the idle to just over 1000rpm, and as soon as I took off and slowed down again, it idled down, and died. It was fast idle 1 minute, then ready to stall the next, basically the same as it's been from day 1? It does appear to run better each time out though. I figure before I get it fixed, I'm gonna wear out the idle speed screw (with it's annoying 11mm locknut), & wear out the starter, thank goodness it starts right back up immediately.

 

[Nate3172]

Re: 89' Force 125hp, Max Rec. RPM range?

Have you checked the reeds? Aside from that, all I can think of would be that one of your inlet needles on one of your carbs is not sealing completely and even though the float is set to spec and not sinking, the fuel is still entering the bowl and overfilling the carb.