Take out thermostat on Tohatsu 8hp 2 stroke?

[boatster]

I just picked up a used Tohatsu 8hp 2 stroke. I did the usual run through, impeller, carb, spark. I was going to do the thermostat and realized that its only accessible by taking off the head. This is most inconvenient to say the least. In any case the thermostat was indeed clogged and had to be cleaned up quite a bit to make it work again. My concern is that it will clog again and I will have to go into the head yet again. Can I simply not put this thermostat back in? I'm using this motor primarily in the Pacific Ocean off Southern California. What is to be lost by removing this thermostat? Or could I just take the restrictor off of the thermostat so that the flow is still restricted some but it will never close down? Thanks.

 

[mattsaks]

Re: Take out thermostat on Tohatsu 8hp 2 stroke?

From experience with larger outboards they run way to cold if you take out the thermostat which is not good for the motor. Someone may have first hand experience with one of these though.<br />I wouldn't recommend it. Why not just fit a new one? What was clogging it up anyway?

 

[boatster]

Re: Take out thermostat on Tohatsu 8hp 2 stroke?

Hi Matt,<br /><br />It was clogged up with salt rocks etc. The previous owner didn't have this motor long (though he bought it new). He was a liveaboard out at the islands and didn't flush it all that well. I'm teetering on puting it back in but I'm thinking of taking off the valve part of the thermostat so at least the flow is restricted. I'm very good with flushing my motors but am a bit concerned since the only way I can check the t-stat is by taking off the head everytime.

 

[TOHATSU GURU]

Re: Take out thermostat on Tohatsu 8hp 2 stroke?

Replace the thermostat and flush the engine...You will not have any further problems with it.

 

[Silvertip]

Re: Take out thermostat on Tohatsu 8hp 2 stroke?

Without a thermostat, the engine runs cold and may eventually develop stuck rings and suffer from carbon build up and piston scuffing. If the engine was intended to run without a thermostat, the designers would not have included one. Install a new one as long you are in there anyway, and flush the engine after use. A trashed power head is far more expensive to repair or replace than a $10.00 thermostat and a little inconvenience.

 

[boatster]

Re: Take out thermostat on Tohatsu 8hp 2 stroke?

Thanks everyone. I'm going to clean out the motor and put the thermostat back in. I cleaned it up and tested it in heated water, it opened. I then put it in cold water and it closed. Repeat repeat repeat, it looks good to go back in. <br /><br />Aside from Salt Away is there a homemade formula for actively removing salt crystals in the block?<br /><br />Thanks again.

 

[TOHATSU GURU]

Re: Take out thermostat on Tohatsu 8hp 2 stroke?

Vinegar

 

[boatster]

Re: Take out thermostat on Tohatsu 8hp 2 stroke?

Thanks Elvin. I'll give the vinegar a shot. Do you know how it compares to something like Salt Away?

 

[TOHATSU GURU]

Re: Take out thermostat on Tohatsu 8hp 2 stroke?

Salt away works well.....Vinegar will work, but you need a 50% solution and it's best to run the engine it, stop and wait 30 minutes and then run it again. Think of vinegar as a field expedient that will work, rather than as a dedicated product that will work really well.

 

[boatster]

Re: Take out thermostat on Tohatsu 8hp 2 stroke?

Hi Elvin,<br /><br />I thoroughly cleaned the thermostat yesterday and ran the motor on the water. When I touch the heads it is very hot. It doesn't pass the "you should be able to put your hand on the head and not have to remove it" test. Is this normal for this little motor? Also the block gets quite hot, not quite too hot to touch but hotter than my Tohatsu 50. The motor pee's strong and other than the temp seems fine. But I'm concerned that its running too hot maybe? Could you shed some light on this for me? Thanks once again.<br /><br />BTW could you tell me roughly how much a new thermostat and head gasket would cost for this motor?

 

[TOHATSU GURU]

Re: Take out thermostat on Tohatsu 8hp 2 stroke?

Sounds like its hot and that can be anything in the cooling system and or a leaking headgasket or cracked block. Around $65.00 for the parts.

 

[boatster]

Re: Take out thermostat on Tohatsu 8hp 2 stroke?

I just checked the spark plugs and found out the wrong ones were being used . I'm going to get the correct ones, I hope the motor will run cooler. I will post the results.

 

[boatster]

Re: Take out thermostat on Tohatsu 8hp 2 stroke?

Motor runs cooler as suspected. I had replaced the head gasket when I went in for the thermostat.<br />I'm glad I don't have to go in and replace another head gasket. I put in ngks and it runs much cooler now.