Thermostat

[mickey117]

85 Evinrude 90hp

motor was overheating so i took off thermostats. when the thermostats were off i noticed sand in the thermostat manifold. checked thermostats for operations both operations fine. could the sand have something to do with the overheating?

thank you

 

[HighTrim]

Re: Thermostat

Drop the lower unit and check the impeller and impeller housing, replace as needed, and flush cooling system with garden hose or compressed air, as well as intake area. Make sure you flush the water/air BOTH up the water line to the t stat housing, then back down to the water line. Also remove the tell tale line and nipple, ensuring they are free of debris.

 

[mickey117]

Re: Thermostat

thanxs chris but whats the deal with the sand or whatever it is.i'm sure i could use the new propeller but i'm trying to feagure out the sand and the overheating relationship .

 

[tashasdaddy]

Re: Thermostat

you have sand in the water cooling system, possibly a partial blockage, or the sand ate up the impeller. if it were mine, i would drop the lower, and open the stats again, and flush the complete cooling system with the hose. frontwards and backwards.

 

[emdsapmgr]

Re: Thermostat

The water circulates through the block first, then goes out of the block through the thermostat housing and down the midsection. If sand made all the way to the thermostat housing, then it is likely elsewhere in the block and has probably damaged the impeller. The sand in the thermostat housing could be restricting water flow out the block-causing an overheat. Check the valve body in the thermostat housing. There are two small pinholes that must be open to prevent overheats. Being so small, they do tend to accumulate debris easily and plug up. If, after cleaning the thermostat housing and a installation of a new impeller, you still have overheats, I'd pull off the head covers and have a look, perhaps even pull the heads and check for sand in the block. High Trim's flushing recommendation is a good idea before you get into head diassembly.

 

[mickey117]

Re: Thermostat

thanx guys,i'm going to pull the lower unit this weekend.can anyone give me some tips,or a heads up on anything.are there other things i might want to take care of while i'm in there.

 

[HighTrim]

Re: Thermostat

When was the impeller/water pump last serviced? The hardest part will be disconnecting/connecting the shift rod. Do you have a manual?

 

[mickey117]

Re: Thermostat

well i do have a manual.as far as the last the impellar was serviced? I have no idea. I purchased the boat two years ago.

 

[HighTrim]

Re: Thermostat

I would get on that ASAP then. Cheap part, but its failure is catastrophic.

 

[mickey117]

Re: Thermostat

well if water is coming out the tell tale is it still working I realize it needs be changed but the catastrophic part scared me. is it to late? If not any advice?

 

[HighTrim]

Re: Thermostat

2 to 3 years is the normal length of time before changing an impeller. Since you are at MINIMUM 2 years, I would do it. The catastrophic consequences come into play if the impeller fails, just check out the price of powerheads. Im sure a new impeller, along with flushing your cooling system, will get you back up and running. This video may help with the install. Good luck.

"http://www.meegsonline.com/tmd/waterpump.wmv"

 

[mickey117]

Re: Thermostat

sounds good, new impellar and a good flushing is on for the weekend.as far as flushing goes how do you flush the system

 

[HighTrim]

Re: Thermostat

When the lu is down, you will notice a water line that runs into the impeller housing. Remove 1 t stat at a time, and blast compressed air or the garden hose up it, ensuring water/air exits at the t stat housing. The backflush the air/water from the t stat housing, ensuring it exits via the water line. Do this numerous times until you are certain that all sand/debris has been removed. Replace t stat, then repeat this for the second t stat, removing it, and flushing and backflushing until all sand/debris has been removed. I would also clean out the water intake area. Clean out the tell tale line and nipple of sand/spiderwebs/debris, etc... Also pay attention to the pinholes that emdsapmgr referred to.

 

[mickey117]

Re: Thermostat

is it a good idea to change the exhaust and shift rod seals as well as drive shaft grommets .i'm reading my manual and i'm not sure of what seals to replace or buy.i'm trying to get a list together but am not sure of want actually comes in the water pump replacment kit (can anyone give a good list)

 

[HighTrim]

Re: Thermostat

A list available here.

http://www.iboats.com/mall/partfind...gd_poid=110968&gd_row=46&**********=511029100

 

[mickey117]

Re: Thermostat

high trim i saw that kit on iboats which is the kit i'm getting but what is the difference between 18-3390 and 18-3392.also how about the exhaust housing?or is this kit simply the only thing i'll need.the manual also said something about a special tool(installer part no:326546)or eqivalent. Is this tool really special or is it just lets say (plires) thankx for everything that video was helpful aswell although it was at the same time funny seeing a pro having a hard time with getting the housing over the impeller,and here we go my friend and I going to try this for the first.just a little scary

 

[HighTrim]

Re: Thermostat

The Sierra kit 18-3392 includes the housing. If yours is scored or damaged, you will need to replace it. Or you could simply order it and have it as a back up, you will not know if you need it until you drop the lu. Everything you need for the water pump is included in that kit, you are describing things unrelated to the water pump.

With your manual, some basic tools and this forum, will be a piece of cake. Good luck.

 

[mickey117]

Re: Thermostat

this is unrelated as well but does iboats sell the drain plug for the lu if so where?

 

[HighTrim]

Re: Thermostat

It is BRP part number 0318544, nylon washers part number 0311598 x 2

The Sierra parts can be found here on iboats, #42 in the diagram.

http://www.iboats.com/Evinrude_Gear...5177498--**********.583526222--view_id.272926

Always remember to put new washers in every time you service the lu oil, usually every Fall.