1985 90hp johnson over heating problem

[mick3446]

I have a 1985 90 Johnson that one side(left) of the v4 block is getting hot...water comes out fine from the spout but the left side is much hotter than then right. I bought the SELCO book but it does not address this issue. Any help would be great. Thanks

 

[ezeke]

Re: 1985 90hp johnson over heating problem

The tell-tale will let you know that the water pump is functional, but tells you nothing about the flow through the cooling passages of the engine.

You may have a weak pump, a blocked thermostat, or the water deflectors may have failed.

I would rebuild the thermostat system first. Sierra kit 18-3673 has everything you normally need for the thermostats: http://www.iboats.com/mall/partfind...gd_poid=111072&gd_row=34&**********=007813832

 

[mick3446]

Re: 1985 90hp johnson over heating problem

The SELCO Book show nothing on thermostat's or where they are on this engine. My model number is J90TLCOS. There two hoses at the bottom of the engine that go in to each head I have taken them off an forced water thru them and they seem clean. The thermostat seems to be the most likely problem but where and how do i change it? Thanks

 

[ezeke]

Re: 1985 90hp johnson over heating problem

The two hoses leading down from the cylinder heads go to the thermostat housing. The thermostats are held in place by springs. You can use the on-line parts catalogs for your model here: http://epc.brp.com/default.aspx?brands=ej&lang=e

Once your motor is up, the thermostat is shown in the "Midsection" diagram.

The water deflectors are located in the cooling passages of the engine block. If they move, the engine will overheat or at the least not cool properly. You would need new head gaskets and a good torque wrench as well as 4 deflectors to correct the problem.

 

[mick3446]

Re: 1985 90hp johnson over heating problem

ezeke,
You have been a great help!!! Maybe you should write a book with the detail required to do most repairs that a boat owner wants to do to save money. Take a look at the web site you sent me even there they do not show the termostats. Funny how this forum seems to be the best palce for the right answers. I'll let you know how things turn out, maybe I can get in water soon!

 

[ezeke]

Re: 1985 90hp johnson over heating problem

The thermostats are #78 on the midsection diagram. If you click on the number 78, it will take you to the line item for the part number.

We don't want to write books, rather we prefer that people purchase the factory service manuals and come here if there is a problem that needs clarification.

There is very little about the V4 crossflow motors that has not been covered numerous times in this forum.

 

[clippers]

Re: 1985 90hp johnson over heating problem

Could you please tell me how to get at the thermostats on the 90 hp johnson (1985) Do I have to take the entire bottom plastic cover off? Many thanks! Glen

 

[diggin4grouper]

Re: 1985 90hp johnson over heating problem

clippers

you have to use a uni joint on a socket wrench to get to the bolts 1/4 inch drive works best though