Raising Motor

[AguaSki]

I have a 1978 Johnson 140 hp on 18 foot Glastron SSV-188. My RPM’s at WOT are about 5,300. I would like to get to at least 5,500 RPM’s, and possibly higher. My prop is a SS 14.25 X 15 Rapture. Top GPS verified speed is 38 mph.<br /><br />I am considering raising my motor. Currently the AV plate seems about even with the bottom of the boat, possibly slightly below the bottom of the boat. I still familiarizing myself with boats so I have some questions.<br /><br />Without special equipment, can I use the boat trailer to raise the motor? I am thinking I can lower the front of the trailer, block the skeg, remove the top bolts and loosen the bottom bolts. As the front of the trailer is raised, the transom will drop. I will only raise the motor by one hole. Will this work? Is it safe? What could go wrong?<br /><br />The bolts looks to have some type of silicon around them. I assume I will need to replace the silicon. Do I also need to do anything to the hole inside the transom?<br /><br />I will only raise one hole at a time. Is there a rule of thumb used to determine how much additional RMP is gained per each hole?<br /><br />Any additional hints on doing this?

 

[rickdb1boat]

Re: Raising Motor

That will work! And yes, Seal the holes back up....It's all trial and error. One hole at a time and test it on the water...

 

[Solittle]

Re: Raising Motor

In addition to watching the tach you need to be careful that you don't raise it so high that the intake for the water pump gets exposed. A pressure gage would help.

 

[AguaSki]

Re: Raising Motor

Where do you find a pressure gauge and how do you connect it? When monitoring pressure, what is the appropriate PSI?

 

[Solittle]

Re: Raising Motor

Use the red Search at the top of the page. There are quite a few posts on this.

 

[Silvertip]

Re: Raising Motor

Water pressure gauges are available right here on iBoats. They can be "T-ed" into the tell tale or if there is a port on the engine that's not being used, it can be connected there. There is no "specific" water pressure but there are some typical values for specific engines. You normally replace the water pump impeller, not the wot and idle pressures. In the future, or during prop testing if you notice a change from what your "normal" readings are you either went too high with the engine or its time to change the impeller.

 

[MajBach]

Re: Raising Motor

I am considering doing the same thing, thanks AquaSKi for that method. To others, I was in the local hardware store the other day and noticed several different kinds of marine sealant from 3M. Which should I (we) use and any pointers on how to apply it?

 

[Boilermaker]

Re: Raising Motor

I tried the trailer method to lift the engine, and although others here recommend it, and use it, I didn't like the way it worked for me. I have a 1978 115HP Johnson with Tilt-n-Trim, and every time I tried to raise the engine the tilt allowed the skeg to kick back. I then tried a 4 ton hydraulic floor jack, but had the same problem>>>the engine kept kicking out from the tilt unit. I went to my local rental shop and rented an engine hoist>>>a "cherry picker" type used in automotive engines. It has a boom arm & hydraulic lift, & VERY GOOD control of the engine! You could even use a "come-along" hanging from a strong tree branch to lift the engine.<br />While I had the engine supported so well I removed all the engine bolts and cleaned them and the transome holes. <br />I then used a marine caulking rated for below water line service>>>I think it was "Life Caulk" >>>I am not a big fan of SIL-LY-CONE. <br />DON'T use 5200 or other PERMANENT sealers. You may want to raise the engine some more, or lower it back, or just service the bolts in the future.<br />Good luck!

 

[tashasdaddy]

Re: Raising Motor

i use a 'cherry picker', but i'm lucky, it's my neighbors.

 

[AguaSki]

Re: Raising Motor

Thanks for the replies.<br /><br />I agree that a ‘cherry picker’ is probably the best option, but as rickdb1boat said, “It's all trial and error.” I don’t think it is practical to go to a rental center each time I decide to make another adjustment.<br /><br />Boilermaker – I understand what you are describing about the skeg kicking back. I did not originally consider this issue, but now I am thinking about securing the entire lower unit to the back of the trailer using a strong strap or rope.

 

[rickdb1boat]

Re: Raising Motor

3M 5200 and smear it inside around the hole and coat the bolt....

 

[tashasdaddy]

Re: Raising Motor

in the old days of unfinished garage ceilings, we would put an 8' 4x4 across the ceiling joist, wrap a chain around it. using a 'come a long' we would pick up engine, and all types of things that we probably should not have. you could still do that, cut a amall hole in the sheet rock for the chain. the hard part will be fishing the 4x4 between the trusses.

 

[tashasdaddy]

Re: Raising Motor

just remembered another thing Dad did. he built us a swing set, using 4x6s 2 up right post set in concrete, cross piece set on top. hook and eyes for the swing chains, but in the center was a large thru bolt, where he would attach the 'come a long'.

 

[Boilermaker]

Re: Raising Motor

Originally posted by rickdb1boat:<br /> 3M 5200 and smear it inside around the hole and coat the bolt....

5200 is the WRONG sealer for this job!!! <br />5200 is made to be permanent! <br /> You will have a heck of a time tring to remove a bolt from your transome if it was sealed with 5200. And according to "Murphys Law", as soon as its made pemanent, you will need to take it apart. <br />Use a NON-PEMANENT Caulking rated for below water line use, Lifecaulk, Silicone, whatever. I think 3-m has a non-permanent version of 5200>>Its 4200 or 4600 something like that, but don't use 5200!

 

[Triton II]

Re: Raising Motor

I recently raised my motor a notch and used a car engine hoist rented from a tool hire place for Aus$25 (about 0.50c US!) for the day. Worked a treat!

 

[rickdb1boat]

Re: Raising Motor

Thanks Boilermaker for the correction. I was thinkin' 4200. Don't know how it came out 5200... Way too permanent.....

 

[andy6374]

Re: Raising Motor

Yep, 4200 or 101.<br /><br />Life Caulk is fine too.

 

[Mike Robinson]

Re: Raising Motor

Aquaski <br /><br />I have used the method you descibe above several times on a Johnson 150 with no problem at all. I'm not sure why Boilermakers skeg would kick out, I don't think that should happen. Maybe the manual release valve is open?