1990 Trophy twin Force 120s prop question

[gica]

The boat came with 4 blade13x19 props but it only maxed at 4400 RPMs at WOT, so I got some 4 blade 13.5x15s and it does max out at 5000RPM now. If I run one engine though after 3000RPM it revs up like it's slipping and the boat doesn't pick up speed, both motors do it, just revs up to max really fast. Below 3k it is ok but it goes slow, no going on plane. I have not raised on engine to see. With both props engaged it takes off fine on a lake. Seems to have good power, 35mps max speed. With the 19s I had 38mph. I don't care about high speed as you cannot really go faster than that in SoCal waters. I have not yet tested it offshore in current. The lake was pretty choppy and current was pretty strong though. I am just worried that it is under propped with the 15s even though the RPM is at 5000 where it should be as the book has it at between 5k and 5.5k. Is this ok or should I go to 17pitch or go back to the 19s? Thanks in advance.

 

[jerryjerry05]

Maybe add a description of the boat??
90 Trophy came with a few different style boats.
The problem is the props are the wrong ones.
They came with 13 1/2 X 17/19p 3 blade.
Like I explained the props are the wrong ones.
Your motors should run 53-5500 rpm.
4400 is too low.
I had a pair of 88/85 that came with 17p props.
I wanted more!!! Changed to a 19p and got more.
The speed went up 2mph from 31 to 33/34 and the fuel economy went
out the window. Used 20-25% more fuel.

 

[gica]

1990 Triphy 2302 twin Firce

Maybe add a description of the boat??
90 Trophy came with a few different style boats.
The problem is the props are the wrong ones.
They came with 13 1/2 X 17/19p 3 blade.
Like I explained the props are the wrong ones.
Your motors should run 53-5500 rpm.
4400 is too low.
I had a pair of 88/85 that came with 17p props.
I wanted more!!! Changed to a 19p and got more.
The speed went up 2mph from 31 to 33/34 and the fuel economy went
out the window. Used 20-25% more fuel.

1999 Trophy 2302 twin Force 120 engines.
I think the boat weighs 3500lbs, but loaded for fishing it weighs at least 500 more. The boat runs great on both moroe now 13.5x15 but when I tried only one it cased the high rev. I guess they are meant for both to be used.

 

[gica]

Maybe add a description of the boat??
90 Trophy came with a few different style boats.
The problem is the props are the wrong ones.
They came with 13 1/2 X 17/19p 3 blade.
Like I explained the props are the wrong ones.
Your motors should run 53-5500 rpm.
4400 is too low.
I had a pair of 88/85 that came with 17p props.
I wanted more!!! Changed to a 19p and got more.
The speed went up 2mph from 31 to 33/34 and the fuel economy went
out the window. Used 20-25% more fuel.

I took off the 19s 4 blades. Do the 3 blades give more RPM? Lets say 3 blade 19th? My friend has a Trophy 19feet with one Mercury 125 has a 13x19 on it. I forgot the max RPM at WOT

 

[jerryjerry05]

The 4 blade is it stainless? The weight difference between stainless and aluminum can be 15# That make the motor turn slower.
Yes add a 4th blade it increases the weight and drops the rpm's.
All 125 hp should run about 52-5400 rpm's.
The boat weight and load and how you run the boat will make a difference in RPM'S
My 21 with 85's and 17p alum ran about 5300 at wide open.
Then add 2-3 fat men and women and a cooler full of ice beer food and coast guard equipment. That can drop the rpm's too.

Contact Bayliner, Hull ID# and ask them about the equipment that came standard with the motors.
You can bet it came with Aluminum props.
I NEVER saw a new Bayliner come off the trailer and or motor box with stainless props.
Someone spent a bunch of $$$ for the stainless props.

 

[gica]

The 4 blade is it stainless? The weight difference between stainless and aluminum can be 15# That make the motor turn slower.
Yes add a 4th blade it increases the weight and drops the rpm's.
All 125 hp should run about 52-5400 rpm's.
The boat weight and load and how you run the boat will make a difference in RPM'S
My 21 with 85's and 17p alum ran about 5300 at wide open.
Then add 2-3 fat men and women and a cooler full of ice beer food and coast guard equipment. That can drop the rpm's too.

Contact Bayliner, Hull ID# and ask them about the equipment that came standard with the motors.
You can bet it came with Aluminum props.
I NEVER saw a new Bayliner come off the trailer and or motor box with stainless props.
Someone spent a bunch of $$$ for the stainless props.

The props are aluminum, as I said the boat weighs 3500 plus additional weight added to it. The boat is a 1990 Trophy cuddy. The engines are 120hp each. You had or worked on those right?
The guy before me had the 13x19 but since the RPM was only getting to 4400 I thought of changing them to 13.5x15
I could not find the 17pitch that fit the 4 inch drive ipening. Most props are for 4.25in mercury or bigger 4.75
Hard to find 4 blade for 4in older drives.
Lime I said the boat goes great with the 15 pitch but only if the 2 engines are used.
Takes off fine gets to 35mph at wot 5000rpm. But when I used one engine only it gets to 3000 and then over revs all of a sudden which means the boat is too heavy for the pitch size by itself. And they both do it. I just want to make sure I can run on one engine if need be.

 

[jerryjerry05]

Had a 21 with twin 85's and 17p props.
It would get it up on plane (1 motor) if it wasn't too loaded.
Your boat actually came standard with a single 125.
The twins was a more expensive model.

 

[The Force power]

Hard to find 4 blade for 4in older drives.
Like I said the boat goes great with the 15 pitch but only if the 2 engines are used.
Takes off fine gets to 35mph at wot 5000rpm. But when I used one engine only it gets to 3000 and then over revs all of a sudden which means the boat is too heavy for the pitch size by itself. And they both do it. I just want to make sure I can run on one engine if need be.

You don't necessary need a 4-blade prop. (this might be the problem)
In my experience & opinion; A 17P to 19P should do the job, either both or one engine running.
I found that a 15P on the 125HP (mounted on a Doral Spirit 2,500LBS) was underpropped & rev too high.
Just picked up a 21P and going to see what it does for me

 

[gica]

You don't necessary need a 4-blade prop. (this might be the problem)
In my experience & opinion; A 17P to 19P should do the job, either both or one engine running.
I found that a 15P on the 125HP (mounted on a Doral Spirit 2,500LBS) was underpropped & rev too high.
Just picked up a 21P and going to see what it does for me

You don't necessary need a 4-blade prop. (this might be the problem)
In my experience & opinion; A 17P to 19P should do the job, either both or one engine running.
I found that a 15P on the 125HP (mounted on a Doral Spirit 2,500LBS) was underpropped & rev too high.
Just picked up a 21P and going to see what it does for me

Thanks The Force Power
So yesterday I took it offshore at Marina del ray. It was a bit choppy 2.5 foot waives coming in slowly plus lots of chop. I could feel it being under propped. But the weird thing was the port engine while also revving up from being underpropped did not slip as quickly as the other engine with the rebuilt drive. if I kept the starboard engine at 2k rpm the port one could act somewhat normal when pressed. If I did the reverse the starboard engine would really rev up to 5k and not do anything for the movement.
So in your opinion 19p 3 blade or 17p 3 blade is better for this. The 4 blade 13x19
did not allow WOT rpm higher than 4400.
can a 3 blade allow rpm to be at the specs level? Again this being a twin setup it should take some pressure off the motors right?

 

[The Force power]

So in your opinion 19p 3 blade or 17p 3 blade is better for this. The 4 blade 13x19
did not allow WOT rpm higher than 4400.
can a 3 blade allow rpm to be at the specs level? Again this being a twin setup it should take some pressure off the motors right?

I'm NO expert and I only know; what I've learned over the years by reading up & my findings on the water.
A 4 blade with a 19P may very well be too much of a pitch for your set-up
A 3 blade with a 19P may work better
(higher pitch more distance travelled per revolution = speed, for fighting current torque is required)
As far as a twin set-up goes (and Force motors in general)...........Jerryjerry is the expert

 

[gica]

I'm NO expert and I only know; what I've learned over the years by reading up & my findings on the water.
A 4 blade with a 19P may very well be too much of a pitch for your set-up
A 3 blade with a 19P may work better
(higher pitch more distance travelled per revolution = speed, for fighting current torque is required)
As far as a twin set-up goes (and Force motors in general)...........Jerryjerry is the expert

Jerry said to call Bayliner and ask them what the originals are on the 1990 Bayliner 2302.
The other issue is finding these damn props for the older 4 inch drives. The newer Mercury are 4.25in

 

[The Force power]

Jerry said to call Bayliner and ask them what the originals are on the 1990 Bayliner 2302.
The other issue is finding these damn props for the older 4 inch drives. The newer Mercury are 4.25in

Yup, same here in Canada

 

[gica]

I did contact lile 5 designated dealers and sent email to Bayliner. Will see what they say.
This is not a high performance boat I am using it to go 30 miles tops usually off tye coast for fishing. So I want to make sure I don't screw up anything being 5hat it is an older boat and engines. One is fully rebuilt top to bottom and that's the one that has all these issues with dying at idle and over revving with the 13.5x15 4 blade prop. It is over revving more obvioulsy tyan the other one. Probably because it has more power and also the drive has all new gears, but the last time I opened it I took off one of the spacers between reverse and front gears because the prop shaft was way to tight. I don't think that will cause over revving.

 

[The Force power]

One is fully rebuilt top to bottom and that's the one that has all these issues with dying at idle and over revving with the 13.5x15 4 blade prop. It is over revving more obvioulsy tyan the other one. Probably because it has more power and also the drive has all new gears, but the last time I opened it I took off one of the spacers between reverse and front gears because the prop shaft was way to tight. I don't think that will cause over revving.

I thought you said with the 4 blade it did not come above 4400 rpms and now you say its overrevving ??
You keep mentioning slipping, how can you tell if one prop is slipping more than the other??
I'm lost! I would have the same prop on each motor

 

[gica]

I thought you said with the 4 blade it did not come above 4400 rpms and now you say its overrevving ??
You keep mentioning slipping, how can you tell if one prop is slipping more than the other??
I'm lost! I would have the same prop on each motor

I have 2 sets of 4 blades. The 13x19 were the 4400, and the ones I bought recently 13.5x15 are over revving . Both are 4 blades.

 

[gica]

I contacted Bayliner and they said since tye model is so old they cannot help me tey to contact a dealer. So I contacted 5 places. One responded they have to contact Bayliner, so wait until Moday.
There has to be people on this site that had twin Force 120s on that 2302 Trophy
If I am not mistaking they had 21 pitch props, I have those aswell came with the boat. The guy replaced them with the 13x19s 4 blades.
These were also given to me. 21 pitch 3 blade probably 13 diameter, no hub. So the giy got tye Solas 13x19 4 blades. I wonder why?

 

[jerryjerry05]

People made the assumption that a 4 blade will be an upgrade and get better performance.
They get better performance if your pulling 3-4 skiers and don't plan on ever going fast again.
Great holeshot.

 

[gica]

People made the assumption that a 4 blade will be an upgrade and get better performance.
They get better performance if your pulling 3-4 skiers and don't plan on ever going fast again.
Great holeshot.

Any idea what size 3 blade I should use. I was thinking 13x19 or I can reuse the 21 pitch that I have but they are missing the press in hubs. Where do I get the hubs?
I am looking online and most are for 4 1/4
drives. And the Michigan Wheel ones like 995112 say they are for 88-94 Force but 85-150. And then there is the 686265-1 or P686-1. They dont mention the size of the back diameter. Any idea where to look for
2 props for tye 4 in drives?

 

[gica]

Ok I found 2 13x19 3 blade props on Ebay that should fit the 4in. The Vortx 992105 from Michigan Wheel. Got reallt good deals on used ones so it's all good. Let's hope they do a better job on RPM than tye 4 blade of the same specs and also the 13.5x15 that over revved.

 

[jerryjerry05]

Keep us posted.