Prop to pad measurement

[Frdtrtnfx4]

So I finally took a prop to pad measurement on my 2017 PT190 and got about 4 1/2" from the pad to the Middle of the prop and the cavitation plate is about 2 1/2" above the pad. Motor is in the top mounting hole as it came from the factory. I was going to raise the motor one hole but now I'm thinking I would lose some performance. Do these measurements sound correct ?

[Princeton_Man]

What are your WOT RPMs and speed now?

[Bud Kennedy]

I don't recall all your issues but since you are already in the top hole, It sounds like you can't raise it anymore unless you are equipped with a jack plate.  Princeton Man asked you the right questions wanting to know RPMs at wide open throttle and what speed are you running.

I still believe your motor is a bit deep but I don't remember all of your original details.

[Frdtrtnfx4]

I'm getting max RPMs running a 19p 4 blade aluminum prop, I can't remember the diameter but I was running the stock 23p black max prop and was only getting about 5200rpms and 44mph with the 115 merc 4 stroke, I knew there was more speed with that motor so now I'm getting 50mph with just myself and then 48-49 with 2 guys and a full load of fishing equipment on board and that's with minimal chop. Once it gets windy the rear end starts getting squirmy and dances so it gets dicey and I need to back off the throttle to 45mph. I thought maybe it was the motor being too low in the water but from talking to other guys with the same boat it just might be the hull design on the trackers. I was going to raise the motor to the second hole from the top but the lifting ring for the motor is very expensive

[Bud Kennedy]

Sounds like it is doing fairly well.  Good luck on moving up another notch.  Will be interesting to hear the results.  Also would be interested if you see any changes of consequence in your water pressure gauge.  I have a hunch the only changes you will see may only be a couple mph

[Princeton_Man]

I have to say, I think I'm in agreement with Bud. Your numbers look pretty good. Looking at the Merc specs for the 115 4stroke, they say full throttle is 5000-6000 RPM and I'm not so sure you want to max out a 4strtoke the same as a two.

If the stern gets loose in the wind now, raising it could make that worse. Design and material has a lot to do with that but if you raise the motor, you could end up with your prop having less bite. While aluminum props are lighter and easy to spin up, aluminum prop blades tend to flex a bit under load which reduces pitch. If it were mine, I'd experiment a little, with props. First thing I'd want to do is try some stainless steel props starting with one that matches your existing prop.

A good marine/prop dealer should work with you and let you try some different props. You could even try posting here that you're looking to borrow try some props. THere might be some folks near you who'd be willing to let you try something they have.

[Frdtrtnfx4]

I played around with props back in May and ended up with a 4 blade prop but I am thinking about switching to a 21p SS prop next year, the prices of the SS props are outrageous.

[Princeton_Man]

I played around with props back in May and ended up with a 4 blade prop but I am thinking about switching to a 21p SS prop next year, the prices of the SS props are outrageous.

I like a 4 blade, the give you best traction. If you can pin point the SS prop you're looking for, some good deals can be had on used ones. Just have to be careful buying online without being able to inspect first.

[gatorglenn]

That squirrelly feel is because your motor is too low.Best results with this motor combo. Is mounted in the 3rd hole down from top. And a 20p 3 blade, Laser ll ss. Or a 19p ss X7 Spitfire.


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