Advice on Engine swap please

[shirthero]

I have a fairly nice old 71 glastron bayflite with a tired '71 60 horse johnson on it, and I just snagged a nice running 76 115 merc with tilt trim. I may be delusional but it doesn't seem like it should be that hard to swap these motors. What do I have to watch out for? How do I adress any "spare" holes in the transom- I'm assuming the bolts won't match up given the difference in years and brands. Also, to show my ignorance, can someone explain to me the two switches on the shifter for the trim, and then there is the 3 buttons on the dash...I only thought I knew how to work tilt and trim I guess! How heavy are these units? Do I hveto have a hoist or can 2 men handle swapping the motors?

 

[JB]

Re: Advice on Engine swap please

Step one is determine the HP rating of your boat.

I really doubt that it is rated for 115HP.

 

[shirthero]

Re: Advice on Engine swap please

She's tagged for upto 115hp on the body plate

 

[jimg984]

Re: Advice on Engine swap please

as JB pointed out check the rating for max. hp also the condition of the transom. the 115 mercury will go around 300 ilbs plus about 40 lbs for power trim pump, etc. the other motor, probably 200 lbs. best to handle both with a hoist. 1/4 inch flat metal plate silconed over the exixting mounting holes, and silcone all holes full. best to use every thing from other boat, controls, wiring, and sterring

 

[shirthero]

Re: Advice on Engine swap please

Ok, got the motor on the boat, filled the extra holes and siliconed everything up good. Now to move the mercontrol and the trim pump/res. The pump is in the boat, the lines go through the splash well via a block that serves as trim and to hold them firm. There is also a sheathed pair? 3? wires that go right near the drivers side hydraulic cylinder, but it is just cut off in the boat by the pump. What is this? The system seemed to be working ok, and it obviously has been cut off laying there a while. Also, I'm assuming there is a main electrical box somewhere back there in the old boat, my johnsons always had a big box between the motor and the command, merc's the same?

 

[Chris1956]

Re: Advice on Engine swap please

There are no external electrical boxes. It sounds like you have it all. The cut wires on the starboard trim bracket is the trim limit switch. it sounds like it broke and was bypassed. Middle and top buttons pressed together trims/tilts the motor. Make sure you fill the pump with 5W-30 or Dextron III ATF, depending on what is already in the pump.

 

[shirthero]

Re: Advice on Engine swap please

So are the throttle mounted buttons redundant to the 3 on the dash then? Is there any difference functionally? Also I noticed a waterproor toggle mounted in the splash well of the boat the motor came off of, I'm guessing this is also a trim switch for convience at the back of the boat? didn't find it till after I had yanked the motor off, is it worth moving it as well, or an unnessecary luxury?

 

[Chris1956]

Re: Advice on Engine swap please

The switch in the splashwell is a luxury, IMO. I have switches on both my newer ourboards, and only use them when the boat is on the trailer. I am not sure you coud reach yours.

The three button control panel was the original one. After they incorporated the PTT function into the throttle handle toggle and trailer button, they DCed the three button control. I do not know how your PTT unit is wired, however, I would use the toggle switch if it could be done easily. If you have a single up solenoid on the PTT unit, the current draw for the down circuit(direct wire thru switch) may be too much for the toggle switch.

 

[shirthero]

Re: Advice on Engine swap please

I have a few wires I need some help with, routed in with the control cables. I have 3 wired in a sleeve, white green and black, it appears to me they go to a kill switch, the switch was taped together and buried under the dash, the motor was on bass boat so I'm sure thats what it is. Zip tied with this, also coming in with the cables is a single black wire. Not a clue on this one could not trace it and forced to cut it. Any thoughts?

 

[shirthero]

Re: Advice on Engine swap please

Still wondering about those wires above, but have another issue:
#4 plug wire is toast on the distributor end, thought okay cap rotar and wires...but you can't get the cap anymore?!? Suppose I can fix the end of the one wire and clean out the fitting on the cap, suggestions????

 

[Chris1956]

Re: Advice on Engine swap please

The plug wires can be purchased thru vintageoutbaords.com. The cap can alos likely be purchased but the cost is high ($100+). The rotors are non-replaceable. The rotor and shaft is $200+. See if you can clean up the cap and rotor wit some very find sandpaper. Clean out the old wire and replace it.

BTW - the wires screw into the dissy cap

That motor has a battery-driven CDI ignition. Therefore the kill switch wires you have may not work.

BTW- You need to have +12V on the white wire on the starboard side of the switchbox to have any spark. The red wire above the white wire is "hot" all the time.