Help with motor height adjustment

[Texasmark]

Agree on some props designed for stern lift, and others for bow lift. Just depends on the application. I am currently running a 4 blade Solace SS on my 2002 1750 Crestliner Fish Hawk with a 2002 Mercury 115 2 stroke for that very reason in 19 P.....(running a 2:1 gear box on the 115). I had a 20P Laser II just to see what the boat would do and now that I know time to be realistic for a senior citizen.

I'm all excited for you because I think you are where you have been looking to be. Do want to know the answer.

 

[orositevuv]

same thing I bought from Marine equipment online store

 

[Texasmark]

We haven't heard from the thread originator "Monkeybird747" since somebody took the liberty to move this thread from where it was. You don't suppose he couldn't find it to tell us how his latest and hopefully final test ran???????

 

[MonkeyBird747]

I didn’t get lost! I have fresh info and videos. Took the boat out for a run. As a reminder, this was with the jackplate removed and AV plate about 1.5” above the keel. The boat handles really well! I lost maybe 1-2mph on the gps, but the porpoising was reduced. Trimming up to the sweet spot still yields a slight porpoise though. I have to leave the trim very near the full down position. The plate above the AV plate (name?) looks to be about an inch above the water at WOT. Have a little right pull, and I have one more notch on the torque tab I can use to try and correct for it.

The spray off the hull at the transom is vastly improved. The new transducer location looks to be spot on to me, and you can see it is just skimming the top of the water.

I think I’m about where I need to be. I have one more motor mounting hole I can go up to, which I think is about 3/4” difference. Not sure it’s needed though. Also I had already considered getting some ProTroller smart tabs that double as auto trim tabs. That might take care of the residual porpoise.

Check out the new videos. If you compare to the ones from the first posting you’ll see the big difference in spray. I tried to get a few different angles so you can get a feel for how the boat runs on the water. This is with three full grown men on the boat. About 34mph WOT gps. I offloaded two of them and took it out solo and was 36mph at I think around 5300 rpm. Carved around a bit and pushed up the power in some hard turns and no blow outs.

Looking forward to everyone’s thoughts.

 

[racerone]

Agreed that JOHNZUKI belongs on the 20" transom with no jackplate.

 

[Texasmark]

If you want to spend some money on a prop, get the same number of blade as you currently running, SS with variable pitched, cupped blade tips and most importantly, high "rake". Expect it to load the engine more than your TP Hustler even though it has a lot of what I mention below.and you might want to drop an inch or two if you run with 3 guys most of the time.

The cupped tips help to hold you in turns and at high trim angles, reducing blowout. The rake is like putting the prop in a tube and pointing the tube which way you want the bow of the boat to go. It may change your "aspect ratio" (I'll call it for lack of another word) of your speed vs trim angle to control porpoising.

One more question to be answered. Considering the Hustler has ports which help you out of the hole, do you want ports in another prop or not?

I didn't mention it (forgot) in my prior posting on your problem, but my slip on my Hustlers was right at 24% as I was leveling off from the hole shot and dropped to 7% at WOT just to give you a number for what the holes do for letting the RPMs get up fast. Again, that amounted to about 1k RPM increase over a prop without holes and most of the same characteristics and blade count.
Glad on your success and glad the post didn't get lost.

 

[Texasmark]

If you want to spend some money on a prop, get the same number of blade as you currently running, SS with variable pitched, cupped blade tips and most importantly, high "rake". Expect it to load the engine more than your TP Hustler even though it has a lot of what I mention below.and you might want to drop an inch or two if you run with 3 guys most of the time.

The cupped tips help to hold you in turns and at high trim angles, reducing blowout. The rake is like putting the prop in a tube and pointing the tube which way you want the bow of the boat to go. It may change your "aspect ratio" (I'll call it for lack of another word) of your speed vs trim angle to control porpoising.

One more question to be answered. Considering the Hustler has ports which help you out of the hole, do you want ports in another prop or not?

I didn't mention it (forgot) in my prior posting on your problem, but my slip on my Hustlers was right at 24% as I was leveling off from the hole shot and dropped to 7% at WOT just to give you a number for what the holes do for letting the RPMs get up fast. Again, that amounted to about 1k RPM increase over a prop without holes and most of the same characteristics and blade count.
Glad on your success and glad the post didn't get lost.

I didn't include it here as I didn't look closely at your pictures but I like what I see. You have enough water over the AV plate to do what you want with that setup, for top end. rough water running, and pullinng water toys. At that height you have enough water over the prop to run about any trim you want and I see no reason why you can't control the porpoising....unless there is something wrong with the hull....like maybe a "hook".......being a bottom that isn't straight where it was designed to be straight...had a bow in it about midship or preceding the transom.

You might check it by getting a straight piece of lumber...say 8' 1x4, and put it vertical at the transom and directly forward. There shouldn't be any place along the board that you see light between the hull and the board until you get far enough forward for the bow rise to deliberately leave the flat plane. Poor trailer support, and years sitting on it, is the main cause, mainly on boats sitting out in the yard, uncovered with the owner forgetting to pull lthe drain plug or it getting clogged with leaves and such.

 

[Sea Rider]

Removing the jack plate was the right thing to do, now can play with different lower leg heights while the motor sits flat on transom.

Happy Boating​

 

[MonkeyBird747]

Well, here is my final update. Took the boat out today with a 13x23 TP 4-blade prop just to see how it would run. The boat performed great. Still hitting 5300-5500 rpm depending on how I trim. Three people in the boat which eliminated the porpoise. Could trim pretty much wherever I wanted to. I can also fill up the 15 gallon live well for some ballast if needed. Plenty of hole shot left and gets on plane quickly.

A topic for another thread, but the only odd occurrence was my trim suddenly ran away full up like a switch was stuck. It blew out in cruise and caught me by surprise! Tried the transom and throttle switches and all I could do was stop it by holding opposite trim. I scrambled to get to the battery to pull the wires before something burned up or caught fire. About the time I got to the battery it stopped running and was normal again. Next install will be a main battery switch/selector.

Thanks to everyone for the advise. The boat is running right where I want it now.

MB

 

[Texasmark]

Well, here is my final update. Took the boat out today with a 13x23 TP 4-blade prop just to see how it would run. The boat performed great. Still hitting 5300-5500 rpm depending on how I trim. Three people in the boat which eliminated the porpoise. Could trim pretty much wherever I wanted to. I can also fill up the 15 gallon live well for some ballast if needed. Plenty of hole shot left and gets on plane quickly.

A topic for another thread, but the only odd occurrence was my trim suddenly ran away full up like a switch was stuck. It blew out in cruise and caught me by surprise! Tried the transom and throttle switches and all I could do was stop it by holding opposite trim. I scrambled to get to the battery to pull the wires before something burned up or caught fire. About the time I got to the battery it stopped running and was normal again. Next install will be a main battery switch/selector.

Thanks to everyone for the advise. The boat is running right where I want it now.

MB

Replace your trim relays. The Up/Down SP OFF DT spring loaded switch is controlling "signal" power (low wattage) to operate the solenoids in the relays. The relay/solenoid contacts do the work. If you were around in the days of ignition systems with points and condenser (capacitor) and noticed the pitting of the contacts when they get old......relays/solenoids do the same thing. Over time the contact surface gets so small that the normal current running through the relay has such a small area through which to run that it elevates the metallic temperature to the point where the points "weld" themselves together! When that happens you can remove the energizing current and the circuit will remain closed like happened to you.....my best guess.

On your success, congratulations. Thanks for staying with us on it and thanks for telling us....the conclusion. Way too often folks come on forums and ask all kinds of questions about problems and then disappear...who knows whether you helped them or what. Knowing gives you confidence on how you feel about helping the next person.