Advice on installing outboard engine on old pontoon

[thormx11]

About 3 years ago I rebuilt a 24 foot pontoon boat for a family member, from the pontoons up. It was an old (70s maybe) pontoon that had been sitting in the woods uncovered for 20 years or so. There was no motor on the boat, so I did nothing as far as steering/wiring/enging.

The boat had an older style transom, a 4 foot long 2''x10'' board that was adjustable by a large handle. I assume this is how you would have adjusted the tilt/trim before the power tilt/trim came along. I replaced the 2x10, but that was about it.

Now they are ready to install an engine and get the boat running and have asked me to help. I have little boat mechanic experience, but I am an auto mechanic and change engines in vehicles almost weekly, so I know how to turn a wrench pretty well.

I believe they bought an 80s model 40hp mercury that was supposed to be complete with the steering, and possibly power tilt/trim.

So my question is, what kind of work is involved in hooking up an engine on an old pontoon? I believe they also purchased a new pontoon wiring harness from online to go along with the engine. I don't believe there were many gauges that would need wired up. I wouldnt have a problem running fuel lines or battery cables. But how much is involved in setting it in place, hooking up the wiring, and getting it to run?

Also, if the engine does have power tilt/trim, what is involved in hooking up this system? Or would they be better off keeping the old adjustable transom setup?
The boat is about 1000 miles away from me right now. I'd like to make sure it is something I would be capable of doing before driving down there.

 

[211libwtfo]

Ain't nothing but to do it. Get your center point and center up the motor. I'm sure it's got T-handle clamp for transom. I would lock that old tilting transom down to optimize the motors self contained tilt/trim system. I think it'll all be self explanatory when you get there. Is there a helm and steering? Have them send some pics of motor and transom and post here.

 

[ondarvr]

Putting the motor on is easy and quick, set it on the transom and tighten the bolts. Hooking things up like the steering is a bit more involved unless the steering system is already in place, then it's easy (you said the motor came with steering, that would be odd). It will need all the throttle and shift controls, this may have been included, just run them to where you want.

​The trim and tilt needs nothing, it all comes on the motor and ready to go, nothing for you to do.

​There wouldn't be a "pontoon wiring harness", there might be an extension kit thought, it just depends on where the helm is mounted.

​Getting an old 1980s Merc running that's been sitting around will be a bigger challenge

​And since we can't see the transom, you'll need to be the judge of how strong it is

 

[wrench 3]

There is no standard length for steering, gearshift and throttle cables. So you will need to find out what lengths you need and maybe purchase new ones. You will need to open up the control box to change the cables but it's not that complicated. They quick connect at the engine.
The original wiring harness is a single plug at the engine and a couple of single connectors for the trim. There would be a plug in on the control box for power and ground to the gauges and a tack feed. The fuel gauge is wired separately but is the same as an older car.
When mounting the engine the anti cavitation plate should be roughly level with the bottom of the pontoons. If not you may have to modify the 2X10.
I've probably forgotten something but it's a start.

I'd put bolts in the engine mount for security.

 

[thormx11]

Thanks for the quick responses. I took a look at the motor she had bought, but it has been about 2 years ago. At the time, it was just laying on a pallet, but if I remember correctly, it had the steering wheel & cables, and the shift/throttle cables and wiring hooked to the controls. I am not sure what boat they came off though, I do know that a pontoon engine would have to have a longer/deeper lower unit than say a bass boat though right I did put the helm and guages on the boat if i remember, but no wiring. Here is a link to the wiring harness I am thinking of, either she had already bought it, or I had told her she would need it before putting the engine on.

http://www.pontoonstuff.com/collections/pontoon-boat-parts/products/pontoon-boat-wiring-harness

I am waiting for her to call me back with more details about the engine.

 

[wrench 3]

That wiring harness has nothing to do with the engine and controls. Take a look at the installation diagram on the web site.

 

[Scott Danforth]

Not sure if the old handle adjustable pontoon motor mount is rated for 40hp. Most i have seen had 20hp motors on them