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'06 MA 18.5 Prop Setup


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Hello everyone, need some feedback on my '06 18.5 MA set up.

Current setup is - F150, 4" Atlas Jackplate, with a OFX19 Prop.  Does pretty good, able to get 50mph at around 5900-6000 rpm trimmed up.  Hole shot is good.

Few things I'm noticing;  loosing grip (slipping/caveating) at lower speeds and turning. Very noticable.

                                           Trouble getting the bow up when on plane.  Feels like motor and trim tabs are working against each other when I trim it up.

Few options come to mind.  Keep the prop and lose the jackplate. Lifting the JP just a little the prop starts to blow-out so isn't much use to me now. Actually, a recommendation from my local service dept.

                                                    Shop props and keep the jackplate

Greatly appreciate any feedback or opinions, and curious what others are doing with a similar set up.

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I am running a similar setup. Except no jack plate and a Yamaha Reliance prop. The OX19 prop I bought the boat with was trash so I bought the Reliance off craigslist. Its 18P, I'm only getting 5300 rpm's and 44mph with my F150 in freshwater, so I assume saltwater would get me to 45mph. Holeshot is good.  Motor sounds good, but just doesn't have the top end. Thinking of trying the 15P reliance, but not sure what to do also. If you are in the south Florida area you could try my prop and see how it performs for you.

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Wow - surprising to hear your experience eFlat.  I've been wanting to switch over to the 4 blade OFX from PowerTech TRO4 model to improve hole shot and bad slip when turning.  Other posts I've seen suggest that the OFX can be a cure all.  Maybe not always.

I have a 2000 MA hull,  a HPDI 175 vmax, and a jack plate with the bolts in the top motor mount holes (lowest motor). With a 4 blade TRO 20 pitch I can touch mid 50's spinning around 5200 rpm depending on load and trim so it seems to be a good pitch for that motor (max rpm is 5500).   I think the prop is slipping/ventilating when the jack plate is above 2 or so.  Hole shot is decent, but not as great as great as I think it could be.  I'm not a speed freak so would rather maximize low and mid range performance.  The PowerTech guys suggested I try an OFX4-18p.

Regarding the flat ride, I think that may be how these hulls ride.  When I see photos, the boat seems to be at a good angle.  But I agree, it sure 'feels' flat.  

On the jack plate, I like the flexibility it offers when idling in shallower waters.  But despite research, I don't feel like I know how to properly use it - I notice any meaningful changes when underway.  I hate seeing guys blasting over flats and shallow water - just because the prop doesn't get ripped off, doesn't mean the habitat isn't getting damaged by prop wash.

If I find an OFX4-18p I'll post a comparison.

Good luck,


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