MX 1825 engine height

The F200 Yam. on my MX 1825 is mounted in the 3rd hole. I have been disappointed in the hole shot. If this mount height was a hole lower would it help the hole shot?
What hole is your engine mounted at?

Generally speaking that would decrease your hole shot. There would be more motor in the water thus creating more drag. Only time it may help is if you can feel the prop slipping meaning its not able to grab enough water.

What prop are you running?

Isn’t it interesting that a company that prides itself on engineering and creative ideas can not see to mark the size and pitch on the outside of the prop like Mercury has done almost forever.
Anyway I took the prop off and it is a Yamaha prop 14 1/4 x 20.
(Sorry for the rant)

The two Yami props I had for my last boat were labeled on the outside. That could have changed as my boat was a 2003.

FDR

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Isn’t it interesting that a company that prides itself on engineering and creative ideas can not see to mark the size and pitch on the outside of the prop like Mercury has done almost forever.
Anyway I took the prop off and it is a Yamaha prop 14 1/4 x 20.
(Sorry for the rant)

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I know of very very few Yamaha props that don’t have it marked on the outside.
On the outside of the prop on the barrel does it say 20M anywhere?

If there is no markings on the outside of the prop Im going to guess its not a Yamaha prop.

a 20p prop seems a little big based of the testing we have done.
What are you running for RPMS at WOT and full trim?

Most of the boats that left here with that combo have left with a 18p reliance.

Is this a yamaha branded prop?

Sure is. Does it have a stamp at the end of the barrel that says 20M?

No, but in answer to previous ?? It is turning just over 6k at WOT

Something is very odd. I have no idea what that prop is if its not stamped on the outside. Does it have vent holes near the front of the prop?

The only thing I can think of is the following.
That is a performance series prop. The poor hole shot is caused by the size of the prop, it is too big. The only way I can see you getting that many rpms out of that prop and boat is if your trimmed all the way up and the prop isn’t holding water and letting it spin faster.

Im not sure who your dealer was but I would talk to them and see if they will let you try an 18p reliance. I believe that will solve your issues.
If you are anywhere near our Chippewa or Ramsey stores more than willing to let you try one here before you buy one.

Eric;
I bought the boat from TimBukTu in Cook MN. I’ll ask Dave if he recalls or has records as to which prop it is. When I open the throttle the tack jump to about 4k when coming out of the hole. Would bigger vent holes give me more slippage at that point and better hole shot?
Since the RPM are good at WOT and I am running about 53 mph maybe I should just put a cavitation plate.

The tach jumping that high, that soon, tells me the prop is slipping and not grabbing enough water.
Generally speaking that motor shouldn’t have a prop on it with vent holes. If the vent hole size was increased it would create more slippage, that is correct but it will actually reduce the hole shot and create more RPM’s at WOT.
The speed and RPM’s at WOT are right about where they should be though.

I would still strongly suggest trying a 18p reliance as it will hold a lot more water and increase your hole shot and should be able to run about the same RPM and speeds at WOT

Eric;
With that info maybe I should try plugging the vent holes.

If you plug them and still run the 20p prop its going to get even worse. It wont be able to spin that big of a prop without any type of slippage.
You can try it though just to see.

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If the vent hole size was increased it would create more slippage, that is correct but it will actually reduce the hole shot and create more RPM’s at WOT.

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Eric,
Sorry for the hijack, but I was under the impression that vent holes make no difference at WOT/top speed. Do you usually see a measurable increase in WOT rpms with the holes open?

HRG

Eric;
I Tried plugging the vent holes in a VERY crude but effective way. I just put a piece of duct tape over the hole on the inside of the prop. All 3 pieces still there after burning almost 1/2 tank of gas.

WOW what a difference in coming out of the hole. With 5/16″ holes open it was about 7-8 seconds to be up on plane. Today in less that 4 seconds I am up and going.
Still turn 6200 at WOT running 51 MPH.

You won’t notice nearly the difference at wot with the vent holes compared to hole shot. Maybe a couple hundred at most. When your already pushing 6100 or 6200 rims it will make a difference though.

I’m going to guess you had a fairly light load? If you run a light load most of the time you may be able to get away with a 20p. If you run 3 or 4 people and decent amount of gear you will probably want a 18 or maybe 19. You do want a prop without vent holes though.

Thank you sir!

HRG