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brew1891

PT OFX4 prop help

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Picked up a used PT OFX4 19P a while back. Boat is an 03 2200v with small block 200 HPDI VMAX. The boat drifts to starboard under power. Turns either way fine, just requires pretty constant correction to port. I think it’s more noticeable at mid range. Recently flushed the hydraulic steering. Oil was somewhat dirty but not horrible. Feels a lot better just in general turning. No leaks. Correct amount of turns lock to lock. The prop or torque steer seems to be the cause. I have the trailing edge of the zinc fin all the way to starboard. Is this common with the OFX4? I don’t recall the previous Merc 3 blade pulling starboard. At least not this bad. Does the Merc Rev 4 pull this bad? Not a prop guy so I’d appreciate some help. My previous HB with a 90 and 4 blade PT prop didn’t pull at all. It was point and shoot but maybe it’s the 90 vs 200 HP thing. Thanks. 

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I believe you have the "zink fin" pointed the wrong way. Try just running it straight ahead. With hydraulic steering, you should not feel any "pull". 

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Thanks. I’ll try to center the fin and see what happens. Just set it based on THT threads. Found some threads from sea star experts with some tests I need to do. I saw a thread somewhere discussing prop steer on OFX props. Wondering if anyone had similar experiences. 

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I have that prop in 20 pitch, it came with my 23' when I bought it. I noticed a considerable amount of pull (can't remember which way) and it was difficult to steer at speeds above 40-45. I'm talking brace against the leaning post and get into it pretty good, especially around 52-55 mph. I have run the Rev 4, but not for any period of time and I don't recall the steering feedback being an issue. I currently run a Merc. Bravo 1 FS, and it turns freely and as one would expect and at any speed. I will say you can't break that OFX/4 loose and if you do, you're probably going to eject yourself from the boat. I also picked up 6+ mph going to the Bravo and picked up a considerable amount range/mpg.

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On 1/10/2019 at 1:56 PM, RockyG said:

I believe you have the "zink fin" pointed the wrong way. Try just running it straight ahead. With hydraulic steering, you should not feel any "pull". 

I too think the zink should be centered. It’s basically a little rudder. So you are turning starboard with the mini rudder. Set it straight and see what it does. 

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Thanks for the responses. Just got back from ENP. Completely forgot to center the zinc fin before we left. My buddy drove the whole time as he is more familiar with ENP. Thinking it might be the check valves in the helm. Can slowly turn the wheel counter clockwise under power and it won’t move the ram. I think my next task is to remove and clean the check valves on the helm.

BradM—looks like the Bravo 1fs starts at 20 pitch. Not sure I can turn that with the small block 200?

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Not to step on any toes here but pitch to pitch the OFX and Bravo spin completely different. The OFX is tough to spin for its pitch while the Bravo spins easier for its pitch. On my 3.3 HPDI I spin a 22 OFX to about 57-5800 rpm. I tried a Bravo 22 and without much trim hit 6k. I have a 23 Bravo that has had work done by Rich to add cup and still spin that to 59-6000. I even tried a 25 Bravo and was around 5600rpm. By no means am I saying go drop the $$ on a Bravo but if you can get your hands on one to try it is worth a shot.

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To answer the OP original question......

I just installed a PT OFX4 16p on my 2200 TRS 150 Yamaha. The pic below (sorry it's sideways) shows my trim tab is nearly straight in line with the lower unit. It has no pull to either side at any speed or trim position that I could feel. 

I am happy with the performance of the prop. I lost about 2 mph of top speed but it's improved in every other area. I was able to turn 5900 rpm at 43 mph with one person, full fuel, and fishing gear. I'm sure I could try 9 more props and find something that is "better", but I'd rather spend that time and cash catching fish.  

I would like to thank the good folks on this forum. Your post encouraged me to buy this prop, and I could not be happier with it.  :)

IMG_1026.JPG

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2 hours ago, mulligan said:

Not to step on any toes here but pitch to pitch the OFX and Bravo spin completely different. The OFX is tough to spin for its pitch while the Bravo spins easier for its pitch. On my 3.3 HPDI I spin a 22 OFX to about 57-5800 rpm. I tried a Bravo 22 and without much trim hit 6k. I have a 23 Bravo that has had work done by Rich to add cup and still spin that to 59-6000. I even tried a 25 Bravo and was around 5600rpm. By no means am I saying go drop the $$ on a Bravo but if you can get your hands on one to try it is worth a shot.

Not stepping on my toes. I know nothing about props. Bravo sounds like a good prop. HB had the props dialed in on my last 2 boats so never had to worry/learn.

I think I need to figure out the steering issue first and go from there. I will reset the torque tab to center. Once the steering is resolved I’ll worry about props. 

Rocky—thanks for the info 

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Little update. A little while back after a quick fishing trip a buddy helped me pull the helm. We found a small piece of metal in one of the check valves. Looked like a piece from when they cut the internal threads in the helm that finally came off the end of the cut maybe. Our best guess. Refilled and flushed the helm. Straightened out the torque tab also. 

Then the kitchen cabinets/ house re-tile project started. And the boat has sat. So no update on the pulling  

Any recommendations on where to send the OFX for a tune up? Looking a little rough. Don’t need it turned into a racing prop. Just a refresh. Don’t mind mailing it off. Our local prop shop not known for quick turnaround.  

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I would send my OFX back to Power Tech , because they originally manufactured the prop and have all the information from the initial machining process. Contact....Marcus Clemons also known as Funkey Monkey on this forum at 318-688-1970

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Marcus recommends sending it to them and that's knowing I have one of their best shops in my town. Unfortunately due to design it is best sent back to them and not done locally. 

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Steve’s Custom Propellers can get it right, too. They’re located in Quitman, TX. I sent my old PowerTech to them every year for a tune up. 

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Thanks again. 

Wondering if I should run the boat and verify numbers before sending it off. Never done this but the prop definitely isn’t in factory condition so is it a waste of time? I know it goes faster than I wanna go lol. I think it got up to 5100-5300 rpm running WOT on the outside down in Choko. (Max 5500 per the manual) 

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2 hours ago, brew1891 said:

Thanks again. 

Wondering if I should run the boat and verify numbers before sending it off. Never done this but the prop definitely isn’t in factory condition so is it a waste of time? I know it goes faster than I wanna go lol. I think it got up to 5100-5300 rpm running WOT on the outside down in Choko. (Max 5500 per the manual) 

Measure the overall O.D. and if it is more than a 1/4" less than the factory O.D., it's junk. And yes, you should run it and record time to plane and if there is any cavitation present, lowest speed on plane, mid-range acceleration and "blow out" or sliding while turning, top speed; note the RPM at the aforementioned speeds. Also take note of trim adjustment and try to eliminate any jack plate adjustment, if one is present on your boat. I also note where the spray is exiting the hull at cruise and WOT.

There is plenty more info, but for what you're doing the above should be sufficient.

They need data and I subscribe to providing too much is almost enough. If it has a press in hub, have it replaced while it's at the shop. It's another $50-$55 and well worth it.

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