New 4 stroke

[spider1]

Don my brother has a new 4 stroke 150 SN. 2B182247
The motor has a twitch or jerk after 3500 rpms. The dealer says that it's the way the water comes off the hull.
The boat is an older ranger 18'. It had a 175 opti that did not have this problem. Dealer is just trying to blow him off sounds like to me saying nothing is wrong with motor

[EuropeanAM]

What prop/setup was he running with the 175... and what prop/setup is he using with the new 150 Fourstroke?

I'm at least somewhat skeptical of what you've been told.... though more information would be helpful.

Also... look for TRANSDUCERS that are anywhere within 1' from the engine centerline. If one is located within this 2' window, and does disturb water flow, it will result in performance or aeration problems at some point (varies in severity).

[spider1]

I've ask him if he could get a little clip of it running
No transducer. 17psi water.
He had a Lazer2 on the 175 a 25 pitch
He has a 25 Tempest on the 4 stroke.
Boats at shop now so no idea on height. The new motor was mounted in same place as old motor. Not sure if that puts lower unit at same height.
Could the battery have anything to do with it.

[dkibat]

What prop/setup was he running with the 175... and what prop/setup is he using with the new 150 Fourstroke?

I'm at least somewhat skeptical of what you've been told.... though more information would be helpful.

Also... look for TRANSDUCERS that are anywhere within 1' from the engine centerline. If one is located within this 2' window, and does disturb water flow, it will result in performance or aeration problems at some point (varies in severity).

Don i have a Z518 that Ranger installed a SI transducer directly in line of motor center serial #1B941604 with a Tempest Plus 23P what problems if any should i watch for?

[2500]

Don i have a Z518 that Ranger installed a SI transducer directly in line of motor center serial #1B941604 with a Tempest Plus 23P what problems if any should i watch for?

If it's on the kick up at running speeds its out of the water, he's talking on the actual running pad, it's easy for the transducer push water away in turns and prop blades lose bite. Nose or bow drops and boat can hook. If on the z setback like under the step up its fine on a Ranger. My 521 has it in same spot.

[06 SB]

Could it be that the anode behind the prop is coming out of the water and the boat/motor twitches as it exits the water and loses its grip?

06

[xpress spanky]

Could it be that the anode behind the prop is coming out of the water and the boat/motor twitches as it exits the water and loses its grip?

06

If your talking about the trim tab/anode my 150 4 stroke doesn't have the tab, just a flat anode like you cut the tab off.

[xpress spanky]

Connor, if it only does it around 3500 rpms and then it goes away have him try another prop like a 4 blade and see what it does. It makes me wonder if it's at the point that the boat is trying to come up on pad, but could use a little help doing it. I had an old 361V back in the day that would do like that with a 3 blade, but put a 4 blade on it and it did fine. It may not be his problem, but it sure wouldn't hurt to try.

[spider1]

Mike thanks. I think that is what they are going to try next. The owner of the dealership went for a ride and feels like it's a prop problem. So he has changed his tone from his first remarks.

What 4 blade did you go with?

[spider1]

Oh it is 3500 rpm and higher to 5800

[xpress spanky]

I haven't finished propping my rig out just yet, but Brian at Holeshot Propeller sold me a Hill SL4 in a 24" pitch that's a Bravo copy with 4 1" vents that runs out pretty good on my boat. It doesn't have the very best top end, but holeshot and mid range plus handling are very good. I'm going to send it back to him and let him add a little pitch or cup to bring the rpms down just a little because I hit the limiter on top end. I'll also add that at top speed these motors are so quite you can't hear the motor and if you hit the limiter all you get is a surging. It took me a few minutes to figure out what the surging was till I looked at the tach.

[EuropeanAM]

I agree that a 4 Blade prop may help considerably.

I also expect he will be DROPPING to a 24 Pitch prop (expecting a 150 to turn the same pitch that the 175 did (actually, it's a tad steeper) is not realistic.