Another Jack Plate Question

[tecoon]

Hey Guys,

First of all, thanks for the great stuff, I have been visiting this site for a while now and have fun learning from you guys and watching people do all sorts of repairs and modifications...Now I would like some advice/opinions because I'm not quite sure what to do for my situation.

I have a 1988 V20 Dual Console with a 25 inch transom. Until yesterday it had a 1998 Yama 130 outboard on it but there is something majorly wrong with it so I took it off and would like to mount a 1986 200 HP Merc with a 1992 powerhead. The Merc is off my old Glastron, has low hours, and works perfectly.

My question is, should I fill the holes in the transom and redrill for the Merc, or should I get a jack plate and try to use the existing holes? The transom is solid as can be but the Merc is old, and if it only lasts a couple more seasons, I don't want to have to drill another set of holes. Additionally, the Merc's mounting bolts would go into the transom right at the height of the perpendicular horizontal surface (don't know the name) that joins with the transom on the inside wall. So I guess I might have to cut a couple small sections of that out in order to hold the nut in place and then seal it back up somehow?

What are the chances that a jack plate's holes will line up with the transom holes from the Yama? Would drilling a couple new holes in the jack plate weaken it too much?

Here is a link to the jack plate I'm thinking of getting.

http://www.magemarinestore.com/212instsepl.html

Anyone ever use that same one? If so, do you know the vertical dimensions? I'm afraid the Merc's lower mounting bolts may be too low. It looks like it would work for the Yama which does not have as much distance between the upper and lower bolts, but it is questionable for the Merc.

I can take some pictures and post them in a day or two. Right now the merc is hanging about a foot behind the boat on an engine hoist, but I would like to get it on there as soon as I can so I can get out on the water.

Thanks,

David

 

[THEFERMANATOR]

The 2 engines should have the same bolt pattern requiring no modifications. Have you checked to see if it is actually different?

 

[tecoon]

Yeah I checked. The Yamaha bolt pattern looks standard, but the Merc looks like it might be the older pattern...I heard there was a period from late 70's to sometime in the 80's that the bolt pattern was different. Maybe the lower unit is older than I was told?

The bolt patterns look like this (roughly):
o = yamaha
o = merc

oo-------oo


-o-------o-
-o-------o-

Thanks,

David

 

[tecoon]

I went ahead and filled the old holes and drilled the new set of holes. I went with the 3/4" hole, fill will epoxy and redrill 1/2" hole method.

I have a new problem though. The tilt/trim motor goes inside the boat and the trim hoses connect to the lower mounting bolts (which are hollow) to pass the hydraulic fluid to the outside of the transom. The problem is that the bolts were bent when the motor was taken off the last boat, so now they are pretty much useless. I looked into ordering some but apparently it could take a few weeks and I don't want to have to wait that long. Should I just get some standard stainless steel mounting bolts and some longer trim hoses and just run the hoses up and over the top of the transom? Or is that a bad idea.

Thanks,

David

 

[bradford]

I'm no expert, but I feel the less holes in the transom the better. On the bolt issue, as long as they mate with the engine mounting plate properly, I don't see any big deal with running regular stainless steel bolts instead of paying out the wazoo for some from mercury.