Need some help re Lower unit / gearcase info

[stupiddog]

Hi folks,

I have a 1998 4 cyl. Commercial Evinrude 100 HP engine. The Lower unit on the commercial engine is the same size as what is used on a V6 engine, which allows me to use a bigger prop than would fit on a standard/non-commercial 100HP engine's lower unit.

The engine is shot, but the lower unit is in good shape. I have a chance to pick up a 1995 non-commercial 130HP Johnson.

My question is will I be able to swap the larger 1998 Commercial V6 Lower unit onto the 1995 non commercial Johnson? They are both 25 inch shafts.

I use the engine to putt around on a Houseboat and turning a bigger prop is important to me. I am going to look at the '95 engine and run a compression check tomorrow morning.. so ANY help is appreciated!

Many thanks, Scott

 

[boobie]

Re: Need some help re Lower unit / gearcase info

Go on to Shop Evinrude.com and compair part #'s between yrs and HP's.

 

[stupiddog]

Re: Need some help re Lower unit / gearcase info

I did, but I can't seem to find anything that would give a real answer?? The drive shafts and exhaust housings are different numbers between the models, but that isn't surprising with the shafts going into different lower units (V4 vs V6).

I am guessing and By looking at pictures, the splines at the engine end of the drive shaft are the same for each of the engines. If the bolt pattern and shift rod all match, it shouldn't be an issue? Both models use the same water pump housing, so the water tube should match up..But that is a lot of 'if's...

I would hate to buy this engine and not be able to swap out the lower unit. I doubt the owner will let me drop his lower unit and do a test fit.

Scott

 

[Faztbullet]

Re: Need some help re Lower unit / gearcase info

It will fit, all you will have to do is swap the driveshafts and shift rods. A dealer with the DS tool can swap both shafts in about 15 minutes.

 

[stupiddog]

Re: Need some help re Lower unit / gearcase info

It will fit, all you will have to do is swap the driveshafts and shift rods. A dealer with the DS tool can swap both shafts in about 15 minutes.

Thanks! That is encouraging. By drive shafts, do you mean both the upper and lower or just the upper. I just gave the engine a compression test and it has 120 lbs on all four cylinders.

The VRO is disconnected and he runs pre-mix. The engine has been pickled for about 2 years and it was running on a pretty rich gas / oil mixture, that could explain the oily looking plugs.

He said his bottom price is 2K, not sure how good that is though, I will google around and see what they are going for. The trim tilt cylinders have a good bit of corrosion, but I have an assembly on my blown engine that would not be too hard to swap out. The lower unit has a 15 spline prop shaft, is that standard for a V4 lower unit? He has a 15 X 17 prop on it and I did not think a 15" prop fit the v4 LU. Thanks again. Scott

 

[Faztbullet]

Re: Need some help re Lower unit / gearcase info

If its a 13 spline propshaft its the "small case"(3-5/8 dia) and if it has 15 splines its the "large case" (4-5/8 dia) which you already have...

 

[stupiddog]

Re: Need some help re Lower unit / gearcase info

Having the large lower unit is great news and may just make the deal happen. I wasn't sure how many splines were on the large LU, I couldn't get to my old engine to count 'em at this time. Thanks for the help!