Possible Spun Hub PowerTech 4 Blade

[Andrew93]

I recently got some lightly used OSF4’s for my 305 Express with F250’s. Was real happy with the performance of them initially. The last 2 times out I noticed one motor sounds like it is slipping under load. At cruise if I trim up at all the RPMs with dramatically increase on just the port motor.

Curious if anyone has experience with a spun power tech cushion lock hub? Looks like I can replace the rods if that seems to be the culprit.

 

[seasick]

Rods in theory can be replaced. Here is a link to one company but they are out of stock. I don't know how easy or hard it is to replace the rods. You might be better off takin the prop to a prop shop for advice.

Replacement Rods for Powertech Cushion Lok CL200 Hubs (HU-RODS-CL200)

Powertech CL200 cushion lok replacement rods for CL200 Hubs. Consists of 4 white rods and 10 black rods. Works with OFS, OFX, LFS, RKR, VMX, PRO, RXB, ELE, RAF, ELD, and others.

propshopinc.com

Or you can replace the hubs with a different design

Powertech Cushion Lok Hub for Yamaha 115-300 HP (CLYX200)

Powertech CLYX200 cushion lok hub for Yamaha. Consists of a 15 spline hub assembly and rubber anti rattle rings. Works with OFS, OFX, LFS, RKR, VMX, PRO, RXB, ELE, RAF, ELD, and others.

propshopinc.com

 

[Hookup1]

Talk to Ken at www.PropGods.com

 

[DennisG01]

I have no experience with those, but... just thinking out loud...

Spinning a hub is 100% related to the amount of load put on it. The biggest load on a prop is the hole shot. Since it's not spinning there, I don't think the issue is the hub. But go ahead and match-mark the bug to the prop and verify.

Again - just thinking out loud there.

Check for growth on the bottom of the boat or some type of obstruction or even a fouled and/or damaged prop.

 

[seasick]

If the prop has spun and continues to spin under load , an easy way to test for slip is to get both motors running at a slow speed and then jam both throttles all the way forward . If a prop is slipping it will cause a much faster surge in revs than the motor that is not slipping . Just look at your tach data.

 

[Ky Grady]

My Yamaha dealer in Charleston replaced my rods in my PT 4 blade because I had vibration at idle speed. Haven't tried out the new rods yet, but seemed like an easy replacement.

 

[HMBJack]

Andrew,

I have replaced the hubs on my 4 blade PowerTech props a few times.

Seasick's 1st post above references you to the two types of hubs.
Both are good and easy to replace.
A rubber mallet and an oversized socket (like 1" I believe) is all you need to remove (and replace) the hub.

Good luck and you're getting good advice from all the guys on this thread.

 

[Sardinia306Canyon]

At cruise if I trim up at all the RPMs with dramatically increase on just the port motor.

Well, all outboards do that if captain trim's up too much.
Outboards can rise on a different speed so affected side may have been a thad faster then the other and started to ventilate.
As they are new to you propellers i would guess that they are just not the right ones and more sensible to ventilation as the old ones you had before. some pT props are 16 inch wide and if outboard is already mounted high the wider prop diameter can lead to earlier ventilation problems.
Or the port motor propeller has a slight bend, different cup if recupped or invisible damage what let it ventilate earlier then Stbd prop.

As some wrote already, a spun rubber hub will show 1st signs then going over the hump as load is biggest.
Done that a few times hub start to slip earlier and will start to slip at a few knots, first only when accelerating hard and then always.
Not sure about the PT stick hub, i had them but never spun one as i did not used them for long as the PT's did not worked well.

Chris

 

[Andrew93]

Thanks for all the comments. If I throttle up at a normal speed the prop in question RPMs shot up real fast, and when I trim up even a bar on the gauge the RPMs shoot up 600-1000. Next time out I will probably buy the Yamaha 3 blades back on and look into new rods int he hits, it does look easy.

I like the idea of marking the hub/prop and see if it moves also.

 

[seasick]

Thanks for all the comments. If I throttle up at a normal speed the prop in question RPMs shot up real fast, and when I trim up even a bar on the gauge the RPMs shoot up 600-1000. Next time out I will probably buy the Yamaha 3 blades back on and look into new rods int he hits, it does look easy.

I like the idea of marking the hub/prop and see if it moves also.

Sounds like a good plan. It does seem that he prop is slipping on the hub

 

[DennisG01]

If I throttle up at a normal speed the prop in question RPMs shot up real fast,

I think you should have put this info in your first post! With that info, it brings us around to a spun hub as the most likely cause.

 

[Ekea]

yea, marking the hub will remove any doubt. unless it happens to spin a perfect 360 degrees. to counter that, do a hard launch, come back to a stop, trim up, check, then repeat the test.

 

[Ekea]

also, what size are the new props?

 

[seasick]

Thanks for all the comments. If I throttle up at a normal speed the prop in question RPMs shot up real fast, and when I trim up even a bar on the gauge the RPMs shoot up 600-1000. Next time out I will probably buy the Yamaha 3 blades back on and look into new rods int he hits, it does look easy.

I like the idea of marking the hub/prop and see if it moves also.

Sounds like a good plan. It does seem that he prop is slipping on the hub

 

[SmokyMtnGrady]

My Yamaha dealer in Charleston replaced my rods in my PT 4 blade because I had vibration at idle speed. Haven't tried out the new rods yet, but seemed like an easy replacement.

View attachment 35020

Question, I noticed a low speed vibration this boating season . I honestly did not think much of it. So, did they replace the power cushion hub assembly? I thought the rods are part of the rubber insert. Are they separate?

 

[Sardinia306Canyon]

I thought the rods are part of the rubber insert. Are they separate?

My two PT 4-blades props came with a Suzuki hub and bag containing the sticks to install around the hub before installing it inside the prop.

Chris

 

[Ky Grady]

Question, I noticed a low speed vibration this boating season . I honestly did not think much of it. So, did they replace the power cushion hub assembly? I thought the rods are part of the rubber insert. Are they separate?

Rods are the hub per say. They surround the splined center section. They saved them and I could clearly see the ones that were damaged. I haven't run the boat yet and at this point, probably won't until the end of October for my SC trip. I'll have my Yamaha 3 blade with me incase I need to switch back.

 

[Ralph163]

Just replaced the hubs on mine. It’s ridiculously simple. Power tech has videos online with instructions. I believe they also recommend replacing the rods every couple years as part of maintenance