4 blade for skiing

[SkiDad]

I have a Force 125 engine and am thinking of going 4 blade next year - I think I have found a prop that will work but I'm pretty sure the anode will hit the webs in the prop. So I'm thinking of just taking it off - will that hurt anything to just not have it ?

I only run fresh water lakes and trailer after each use.

 

[Sea Rider]

Re: Do i need the Anode ?

Re: Do i need the Anode ?

Anodes prevents Galvanic Corrotion on tail, if removed assume worst corrotion on salt water than in fresh ones. Some engines uses trim tabs, being anodes itself. Used to maintain straight courses at speed.

Happy Boating

 

[SkiDad]

4 blade for skiing

I have a 1985 force 125 on a 19' boat that runs well. I currently run a 15 pitch 3 blade AL (no cup). RPM averages 5000 with normal load / 38 mph. I'm on plane within 4 seconds

I was thinking of going 4 blade next year and wondered if I should stay 15 pitch - will the 15 give me a lot more hole shot or do I really need to drop to 13 to get a marked improvement. I know my speed will drop 2-3 mph and I'm fine with that.

the pull is already pretty strong and I can get up on slalom in 5-6 seconds but I wouldn't mind about 20% more pull

 

[SkiDad]

Re: 4 blade for skiing

why did my threads get combined ? - i did 2 threads b/c there were 2 different questions

 

[floater212]

Re: 4 blade for skiing

you could trim the fins down on the anode, used a reciprocating saw with a metal blade and leave the part that bolts to the motor alone and keep track of it after the season to see how much got eaten away.

 

[jestor68]

Re: 4 blade for skiing

I am not aware of a 4 blade prop made to fit that motor.

Needing to cut, file, or otherwise hack up your lower unit might give you a clue that it is not intended to fit your motor.

Contrary to what some might think, a 4 blade doesn't actually pull better that a 3 blade.

You be better off seeing about getting a 15 pitch prop re-pitched an inch for more pull.

 

[SkiDad]

Re: 4 blade for skiing

you could trim the fins down on the anode, used a reciprocating saw with a metal blade and leave the part that bolts to the motor alone and keep track of it after the season to see how much got eaten away.

Good idea

 

[SkiDad]

Re: 4 blade for skiing

I am not aware of a 4 blade prop made to fit that motor.

Needing to cut, file, or otherwise hack up your lower unit might give you a clue that it is not intended to fit your motor.

Contrary to what some might think, a 4 blade doesn't actually pull better that a 3 blade.

You be better off seeing about getting a 15 pitch prop re-pitched an inch for more pull.

I thought about lowering pitch on my new AL prop but I hate to mess up this nice prop. You are right only Michigan makes a direct fit. Have 3 of those. One is stainless and pulls slightly harder but has too much torque steer for my taste.

I'm pretty sure the Silas Amita 4 will fit. Had someone measure the hub and they said 3-3/4 just like my other props. I probably need to either cut notches in the web or trim the anode or remove it. Only going by pics so I would have to see when I actually get one. Not many props for sale in my area

What makes you say 4 blades won't pull harder ?

 

[Chris1956]

Re: 4 blade for skiing

For a trailered boat, anodes are unnecessary.

 

[dingbat]

Re: 4 blade for skiing

For a trailered boat, anodes are unnecessary.

Any type, except pure H2O, or quantity of water/ moisture can act as an electrolyte. A faulty ground in the boats electrical system can trigger potentials The affects may not be apparent to the untrained eye but corrosion marches on in or out of the water.

 

[Fastatv]

Re: 4 blade for skiing

I have a 1985 force 125 on a 19' boat that runs well. I currently run a 15 pitch 3 blade AL (no cup). RPM averages 5000 with normal load / 38 mph. I'm on plane within 4 seconds

I was thinking of going 4 blade next year and wondered if I should stay 15 pitch - will the 15 give me a lot more hole shot or do I really need to drop to 13 to get a marked improvement. I know my speed will drop 2-3 mph and I'm fine with that.

the pull is already pretty strong and I can get up on slalom in 5-6 seconds but I wouldn't mind about 20% more pull

I have a low horsepower boat, 17 footer, and a 130hp I/O. I changed from a 20 pitch four blade SS prop to a 19 pitch SS Quicksilver prop, had a better hole shot and a better top end speed and the torque steer was eliminated...was terrible with the four blade. Of course I'm not comparing apples to apples as u have a different hull than I do and an outboard as well but you might want to test a four blade...if you can, before you purchase. As I believe someone mentioned, there is a "flat" anode that can be installed on your lower unit if the trim tab style interferes with your prop selection, however, without the trim tab style, you will not be able to adjust for steering torque. Rick

 

[Chris1956]

Re: 4 blade for skiing

Dingbat, Whereas you are correct in theory, in practice, since a trailered boat spends only 4 or 5 hours a week in the water, the corrosion is negligible. I had a boat I kept trailered and used a lot for 10 years. The zinc anodes were not even the least bit pitted.

Once I docked her in the saltwater. I needed new anodes every year.

 

[SkiDad]

Re: 4 blade for skiing

thanks for all the nice replies

My boat only has the anode behind the prop - it's just bolted on there (see pic at top post) - I'll probably just take it off for testing... maybe trim if i want to leave it on - it's the original for 28 years and still looks new. I think you guys answered that question and I appreciate it. I put at least 100 hours of water time on the boat in the last 2 years and it hasn't changed look. My "trim tab" is the exhaust snout - different than what you would see on a mercury and it isn't in the way of the prop.

as for pitch - do you think 15 3 blade to 15 4 blade is enough change or is a 13 pitch in need to really notice the pull for slalom ? I have rpm to work with. 17 pitch puts me at 4500 - my 15 is about 5000.

 

[phillnjack2]

Re: 4 blade for skiing

first of all my sincere condolences to anyone owns a force engine and has never experienced what a real outboard can do.
the force range of engines were a disaster in the power stakes, they were cheap and cheerfull and never meant to be compared to the top flight motors like mercury or omc or Yamaha etc.

now being its a force 125hp you have to think of it as around 85 to 90 hp at the prop if your very lucky as these engines are
way way over rated in the hp department.
a force 125 wont have a hope in hells chance against a good 90hp merc or johnnyrude or Yamaha if all fitted to identical boats.


when people talk of a force engine getting a 19ft boat up on plane in 4 seconds they obviously count very slow.
ive seen brand new ones of these on brand spanking new hulls, they are dreadfully low on power compared to the other
major outboard brands.
this is one of the reason why force engines were doomed and the company went bust.
too many people wanting high performance from a low budget engine that was meant more for leisurly cruise rather
than a all out high speed sports boat.

I would drop to a 13 pitch for water-ski-ing to be sensible, and the engine can then get upto its proper rpm's of 5500 and
have half a chance of staying in its powerband.
at 4500 to 500 its struggling.
if the prop only lets the engine get to 5,000rpm its too big, and a skier puts a lot of strain on the engine when he/ she is
deep water starting or pulling hard from outside the bouys.

many wont like what ive wrote but its true, these engines are not the power they are supposed to be.
they look nice and some have even been known to be reliable if kept well maintained and nursed.
treat the 125 as a 80 to 90hp and youl get what you want from it, expect it to perform like other 125's and you will
always be chasing a dream.
aks anyone who has done dyno tests on force 125 what the average hp was, I bet you will never here of 100 plus.

just remember you need to get maximum wot rpm with a prop, then drop down atleast 1" pitch for ski-ing maybe 2 !!!!!!


p.s what model bayliner 19 is the boat and what year
.

 

[SkiDad]

Re: 4 blade for skiing

Your funny! - But i hear ya - I grew up skiing behind a 15' Mark Twain with a 1973 Merc 115 (Tower of Tower!) I remember my dad picking up that sucker and putting it on - it was 1350.00 brand new. Those prices are long gone! And boy that Merc could fly - i have very fond memories of that sound! Still makes me smile. I'm not sure if it was much better getting out of the hole for slalom skiing, but it had a much faster top end and would easily turn 6000 if we wanted it to. Seems that back then was Merc for speed and Rude for torque. They sold that boat in the mid 80's sadly.

But I'm pretty sold that Force is a decent engine and has decent torque - just no top end - my Dad has had one for nearly 20 years now and only had one issue in all that time (and it was an easy fix) Yeah - not that power the Merc had and I agree that a Merc 90 would shame a force 125 - but still a good engine for skiing if propped right. Both me and my dad are around 220 lbs and can get up behind one on slalom. The one main plus is how easy they are to work on! Gotta be the easiest outboard out there to work on.

I guess my need for more pull came after spending a day behind a Ski Nautique - that boat consistently yanked my butt up on slalom in 2 secs. And yes I can count well - ha ha! I know it's not a fair comparison - 5.7L vs my tinny 1.5L.

My boat really can get on plane in 4 secs - i've timed it with my stop watch. it was 6 seconds with the original 17 pitch. I can't say when I went boat shopping I was looking for a force but when i saw this boat, it was so clean and well maintained that it was too nice to pass up. Starts right up on first crank. I have less that $4000 in my boat, engine and trailer and i was out 20 times this summer - money well spent in my mind.

My dream is a glasstron GT-180 with a 150 E-Tec - but that's not doable at this time.

The boat info is in my signature - it weighs 1250 for the hull. Engine is 300. I'm typically about 2400 lbs with the family aboard.

they don't 'technically' sell a 13 pitch or 4 blade for my engine - that is why I'm looking to get something and mod it to fit.

Not sure why I can't hit more RPM with current prop - my dad has the same engine and prop and can hit 6000. I think it might be hull style (his is a bayliner Cobra) and engine height - i know my engine is at least 2 inches lower in the water than his is.

 

[phillnjack2]

Re: 4 blade for skiing

well that engine is one of the older force engines, infact looks like a Chrysler just rebadged.
now being as its got low water pick up is a big bonus if you only wanted top end !!!!!!!!! jack plate comes to mind ...
but as you want to ski behind it I would leave it where it is and see whats causing the low top end rpms.

do you know the gear ratio or model number to find out a bit about the gear ratio ?

Have you checked that with the lever full throttle that the butterflys in the carbs are fully open ?,
i.e dead level so as to give maximum air in the venture of the carbs.
only needs to be a touch out and youl loose rpm.

could be a throttle stop fitted or cable adjusted wrongly as you should easy see 5500 with the engine on full throttle. just a though.

it could also be the timing is not getting max advance, but if the hole shot is quick then I would say no to that.

sounds like a max throttle position issue to be honest, I would check the butter flys are fully open, don't need it running just move the lever to max throttle in gear like its on water going flat out.

could be a throttle stop in the remote box or cable fitted incorrectly, another 500 to 600 rpm will make a huge difference as it would put the engine in its powerband and that would make huge difference both top end and hole shot.
at the moment I would say youl be lucky to 80% from it as its not getting a chance to realy lay down its power.

get the rpms up then once their you can play with props.
don't bother with 4 blade, you are not going to see much difference in it at all for ski-ing, if it was a 300hp then yes, but too expensive and too hard to find.

you need a nice stainless 13 pitch for slalom or very good ali prop.

by the way, that is one very very clean looking boat and engine set up, no signs of any corrosion and in very nice condition.
nice to see a boat that clean.

you have been very very lucky with your chysler force engines, lets hope it stays that way.
Maybe having the original Chrysler type is and was the better option,


phill

 

[jestor68]

Re: 4 blade for skiing

If you can fit a 4 blade prop, using the same pitch will increase the blade are and not improve acceleration. You'll need to use at least an inch less pitch.

I am surprised sometimes at the ignorance shown by some folks regarding the quality and performance of Force motors.

I have owned two; a 1986 65 and a 1992 120. Both were totally reliable and would run with any other motor of any other brand of like horse power.

 

[SkiDad]

Re: 4 blade for skiing

I believe all the force 125's were 100% Chrysler stuff - even my dad's 1988 version looks almost identical under the hood but is black.

All the force 125's are 1.73:1 gear ratio. I think that is part of the issue. I know some guys put the lower units from the 85hp models (those are 2:1 ) to help with this. I've thought about it b/c didn't want to inherit other issues from an old lower unit. I guess if i got a good deal i might try it.

I have checked my throttle plates in the past and they go flat at full throttle position - i adjusted one carb slightly when I first got the boat and got another 100 rpm out of it. I have not done a full link and sync yet or messed with the timing. I have thought about it but it runs so good other wise. I have adjusted my fuel mixture several times - when I got the boat they were set very wrong - one was 1/2 turn out and the other was 3/4 out. I think the guy thought they were idle adjustment screws. Right now I have them both at 1 turn out - i know that does nothing for speed - but it sure did help my boat idle smoother. I think the bottom carb was way too lean and plugs were too dry.

maybe you are on to something with the throttle cable adjustment - I will give that a go when spring gets here

 

[Frank Acampora]

Re: 4 blade for skiing



All things equal, if you bolt on a 2-1 lower unit you WILL immediately gain 3-5 MPH and a better hole shot. HOWEVER: You must step up 2 pitches in prop. The 125 is a long stroke, short connecting rod, small bore engine. It is dead simple crossflow design with not too good crankcase packing and adequate reeds. You must run it between 5000-5500 RPM to get adequate performance. The 2-1 lower unit allows higher engine RPM while delivering slower prop speed. Turning a higher pitched prop at slower speed reduces the parasitic drag of the prop blades through the water allowing more horsepower available to drive the hull. I suspect that your going to a 13 pitch will reduce performance and you will be unhappy. Typically, on these engines, a stainless prop of the same design and pitch will deliver about 200 RPM more than aluminum.

If the hub diameter is 3 3/4 to 4 inches MANY props NOT listed for Force engines will fit with MINOR modification. In fact, may of the props LISTED for force engines will have interference with the anode or will need a special thrust washer. Do not try to gain clearance for the anode by removing web material. It is easy on an aluminum prop but unless you have a Bridgeport mill, it will be almost impossible to do (neatly) on a stainless prop.

Here are a couple of after-market props including a high rake Ballistic which needed the anode removed and special thrust washer to gain blade clearance at the exhaust snout.

In some cases the anode fins can be cut down and in other cases the anode must be completely removed. Later Force engine did use a anode with no fins so they are available.

See my next post for photos of my 55 MPH Force 125 and some more props. The 125 Force is swinging a 13 X 21 at 5900-6000 RPM

 

[Frank Acampora]

Re: 4 blade for skiing



The blue prop is an aluminum Mercury test prop. The hub was too large so I cut off the internal flange and epoxy glued it inside the actual prop hub. Since your engine is single exhaust and does not exhaust through the prop, it would not be necessary to have the flange at all. So: You can use some Mercury aluminum props.

You will find there is NO performance difference between equal props of closed hub design and exhaust flow-through design.

Did you notice that beautiful, old school racing prop in the second photo? Mercury 15 spline, 13 X 25, two blade solid hub. Look close and you will see a couple of spacers both in frond and behind it.

Chrysler 140.

On a 19 foot boat, unless it is extremely heavy, I would expect your engine to swing a 17 pitch prop at 5000+ RPM. Check compression ratio on all cylinders. Check carbs for full opening, Check for adequate fuel delivery. Clean or replace plugs. Go to the Force forum and watch my video in the stickys: Tutorial. Read the sticky on synchronizing timing and carbs.