[Danforth]

Recentley I asked a very experianced mature marine meckanic for assistance in sorting out my impellor on a 15hp mariner 2 stroke o/b.He sorted it out by getting me the correct impellor, I had been sold the wrong one, and that was from a mariner agent. We found at that time that the thermostat needed replacing- it was naff. It was taken off.He told me that a replacement would be about £40, and adviced not to bother fitting one as "British waters are warm enough", those were his words.I couldnt argue as hes forgotten more than Ill ever know, but it got me thinking and thinking till I gave up then thought Id ask on this site what do you reckon gents? Spend the money or leave it as it is?

 

[Fenlander]

Well if you look on my Bonwitco Repairs thread you'll see I've just replaced mine at that cost. I'm a retired (early!) motor engineer and to me leaving out a stat is not a good idea.

Your engine will be overcooled which could lead to poor combusion and perhaps even plug fouling at lower speeds. I'm no outboard expert but that's my take on it.

I looked for ages for a cheaper stat. There was the correct one on EBay recently but I needed the rubber sealing ring plus gasket too and it didn't have those.

David

 

[Davy Holt]

Hiya,

When I built the "Catchalot" the first time around I was also told to remove the thermostats from the Ford 1.6 XLD engines. I never did and they ran fine for near on 6 years before I upgraded to the 1.8 XLD's still with the thermostats in. We had an old Johnston 5hp that we used as an aux on the old boat, when the thermostat went on it we couldn't get a replacement so left it out.. we had nothing but problems with it after that.

 

[Nos4r2]

We had an old Johnston 5hp that we used as an aux on the old boat, when the thermostat went on it we couldn't get a replacement so left it out.. we had nothing but problems with it after that.

Run one plug grade hotter and it'll help.

 

[Fenlander]

Look on the 'Bay... item 150275866388

Yamaha/Mariner 9.9/15hp stat £11 delivered to your door.... is it the right one for yours??

I would just take issue with the guy saying the sea here is warm enough.... unless in 12" at the beach it isn't....it's cold. At the moment I guess it's about 16degC and the outboard thermostat will not open until around 40degC.

David