2020 Mercury 150 4 stroke planing problem

pestrem · August 12, 2020, 10:08:21 AM

I recently replaced the motor on my Stratus 285 Magnum from a 175 Johnson 2 stroke to a Mercury 150L 4 stroke. I had initial problems getting the boat to get on plane but after dropping the motor down on the plate about an inch, that seemed to be resolved. It will get on plane, but very slowly.
This past weekend I had a friend in the boat with me who tips the scales at about 250 lbs. I had previously fished with others who didn't weigh near that much.
With him in the boat, the only way I could get the boat on plane was for him to get on the front deck until the boat was planed out. I never had that problem with the old motor.
Do I need to drop the motor some more? Get a different pitched prop, or other?
The prop I have on it now is 9531-140-23.

Just made a typo correction on the boat. It's a 285, not 185.

WTodd · August 12, 2020, 10:14:11 AM

You probably have the wrong prop on there. My new Z-18 came with a Fury 24-P and I couldn't get on plane. I had BPS put a Tempest 22P on it and resolved the problem but think a 21 might be better

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pestrem · August 12, 2020, 10:20:40 AM

Thanks for the info. I'll be taking the boat/motor in shortly for the 20 hour checkup and discuss a different prop with the dealer.

WTodd · August 12, 2020, 10:21:34 AM

I didn't mention it but I have the same 4 stroke

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Mike Cork · August 12, 2020, 11:29:35 AM

I'm thinking a 21 pitch prop would be better. I'm assuming the prop is stainless steel? Aluminum will flex and cause these kind of problems.

WTodd · August 12, 2020, 11:31:09 AM

Mine is SS....since they changed mine out I've only had 1 issue with it concerning getting on plane

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pestrem · August 12, 2020, 11:47:55 AM

Just got off the phone with Mercury and the guy there is telling me the same that a couple of you have said, that I need a 21. Got a call into the dealer to discuss with him and am awaiting a return call.

Thanks all!

bluebonnet2 · August 14, 2020, 05:49:13 AM

good morning,

Cbaily foil will do wonders for your problem and they are nice looking...... just saying..my tracker 195 planes in about 20 ft. with a mercury 115pxs, powertech 21.....

good luck.
PURA VIDA,
bluebonnet2

WTodd · August 14, 2020, 06:54:15 AM

While I don't disagree they look good, it doesn't alleviate having the wrong prop and this has been going on for a few years.

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pestrem · August 16, 2020, 01:13:38 PM

Have talked with the dealer I bought the motor from and he's ordered a prop with a 21 degree pitch. It's supposed to be in by tomorrow, Monday. Hope to be able to take the boat out for a run shortly after that.

Will post after that.

Thanks, All

pestrem · August 22, 2020, 04:55:34 PM

Prop update...I got a new prop that is a 14.25 X 21. What a difference!!! With my regular fishing friend (who is in the 250 pound range) and a live well full of water the boat, I was able to get up on plane in short order and by trimming it up I was able to get 5500 rpm and a comfortable 49 mph. With the other prop the max rpm was about 4700 and top speed was 46 mph. I'm not a go-fast kind of guy so I'm good with the 49 mph. The important thing is being able to get the boat on plane without whoever I'm fishing with having to get on the front deck till the boat planes out.
Thanks for the suggestion on the prop pitch.

Looks like the panhandle of Fla, where I am, is going to dodge hurricane Laura. Prayers out for anyone who is in her path or that of Marco.

WTodd · August 22, 2020, 05:14:50 PM

Glad you got it fixed...amazing how many wrong props are ending up on Mercs

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