Is a 1986 Mercury controls interchangeable with a 1990 Mercury

[Imjus4u2nv]

I have been having problem with my 1986 Mercury Tower of Power, 90hp and have come across a 1990 mercury 90hp for pretty cheap. Does anyone know if I can swap the newer engine for the older one without having to buy new controls etc>
Any help is greatly appreciated.

 

[Chris1956]

Re: Is a 1986 Mercury controls interchangeable with a 1990 Mercury

Shift and throttle cable will work as will steering. Fuel can be adapted. The only possible difference is the electrical connection. My '93 Merc has a round plug with about 7 connectors, under the cowling. Is that what you have on the TOP?

 

[Imjus4u2nv]

Re: Is a 1986 Mercury controls interchangeable with a 1990 Mercury

Hey Chris,
I will have to check next time I am at the boat (work has been hetic lately, got the boat out this weekend and winterized it). If I just have to swap out the electrical that's not to bad. When I went to winterize the Grady with the 90hp TOP, went to drain the lower unit oil and it was filled with water, no oil at all (water smelt disgusting though and tings of black in it, but no metal shavings).
Any input on the lower unit (I read ot get it vacumm pressure tested, but was wondering what the worst case scenario is and if its a DIY)?
So now it looks like I need some work on the lower unit, still working on getting spark (which as we discussed is likely the switch boxes, and also concerned about the #3 cylinder that I overheated a while back). Lot of variables with this engine, and afraid to get it sparking to find out I need cylinders rebuilt along with the lower unit. I got a guy looking to sell boat with 90hp mercury 1990 for $500- can't go to wrong (at least I think). Will either swap engine out or get rid of the Grady, will likely keep the 1986 TOP though for the future, if I have & one day to do a complete rebuildI would as this engine kicked butt when it was running.

 

[Chris1956]

Re: Is a 1986 Mercury controls interchangeable with a 1990 Mercury

The seal under the waterpump is easy to change, and fails frequently. Hopefully that is your problem. Of course with suspect spark, and a bad #3 cylinder, it is time to Consider saying uncle.

 

[Jeep Man]

Re: Is a 1986 Mercury controls interchangeable with a 1990 Mercury

As to the controls, if the number of wires do not match, an adapter is available through mercury. I needed one to adapt a newer control to an '02 motor.