Motor Height

[router343]

Can someone tell me if my motor is to high. I have read where the ant cavitation plate should be even with the bottom of the transom, and others say it should be even with the bottom of the pontoons. It is on a 1994 21' Sun tracker fishing barge. It is a 120 HP Force. Also having problems finding the right prop. It had a 23p, but it broke, so I put an 18p prop on it, ran ok but not hitting my max RPM. I want to set up more for sking and tubing right now.

IMG_089888.JPG (1.58 MiB) Viewed 2925 times

[oldmn19]

In my humble opinion it's too low by a bunch. Plus your out of holes to raise it. Your next plan of attach would be a jack plate I guess. Sombody's already had it in every hole availible. Nothing fancy just an adjustable one.

[curtiscapk]

Man you are way low! We pretty much have same toon and motor.... That transom is cut really weird!
heres a pic of mine with new transom. Read the post in my sig for full update.

[ToonGuy]

That picture doesn't tell any thing except that your transom looks terrible. On a 2-log pontoon the ONLY way to tell if your motor is right is to put the boat in the water and run it. You want the cavitition plate to just skim the top of the water at full throttle. Unlike a fiberglass hull or full center tube tri-toon this has nothing to do with where it rides out of the water because the height is effected by the way your boat rides in the water...

[DRock]

I agree that it looks way too low. I went through this earlier this year when i noticed how low mine was. I gained 4-5mph by raising the motor a total of 8 1/4" and that allowed me to go up in prop. Get on the boat and let someone else drive at a normal cruising speed. Trim to where you usually would and go take a look at the motor/cavitation plate while running. If you can't see the cav. plate you're too low.

Check out my thread, watch the videos and look at the pics, should get you in the ballpark.

viewtopic.php?f=2&t=16020&hilit=motor+height&start=0

[Bryden24shp]

Looks to me like the motor is a 25" shaft. Look at the pic, above the lower unit is a 5 inch spacer. You may be able to remove the spacer. If it has the spline adapter in it for the drive shaft, you can just remove the whole thing. Without replacing the drive shaft. Take about 1/2 to pull it. Do a water pump while its off, as well.

[curtiscapk]

Damn you nailed it! I was trying to find the diffence he has an exlpto!(Electric start-xtra long-power trim) not an elpt like mine. I was looking above the cav plate!

[Bryden24shp]

Damn you nailed it! I was trying to find the diffence he has an exlpto!(Electric start-xtra long-power trim) not an elpt like mine. I was looking above the cav plate!

I had one on my old Crestliner years ago. Otherwise I would never have caught it. Pulled it off while changing the water pump, comes right off.

[router343]

Thanks for all of tips and suggestions. I like the idea of removing the spacer, I will give that a shot today. Are there any special instructions I can download or will it be pretty obvious once I start on it. Again I really appreciate all of the help.

[rancherlee]

If the spacer isn't easy to remove you could always rebuild the transom plate with tripled up 3/4 marine ply to raise up the motor. To me it looks like the previous owner cut a lot out of that one to lower the engine for some reason. Being a FORCE 120hp it probibly in the 105HP range for power as ALL Force outboards were crank rated even though everyone else switched to prop rated in the late 80's. Not sure on what gear case ratio you have but I'm thinking a 14x15 or 14x13 would be better suited to your toon for a prop.

[curtiscapk]

If the spacer isn't easy to remove you could always rebuild the transom plate with tripled up 3/4 marine ply to raise up the motor. To me it looks like the previous owner cut a lot out of that one to lower the engine for some reason. Being a FORCE 120hp it probibly in the 105HP range for power as ALL Force outboards were crank rated even though everyone else switched to prop rated in the late 80's. Not sure on what gear case ratio you have but I'm thinking a 14x15 or 14x13 would be better suited to your toon for a prop.

Yep 14 x 13 for me. Pic was with 7 aboard. with 3 aboard I maxed at 5300 at 22.6 I think.(no pic)

[router343]

I measured the distance from the plate to the bottom of the transom mount and it is 25", so at this point looks like I will have to go with a jack plate. Thanks for all of yalls help.