Thermostat Replacement

[Cariboo Milkman]

Can anyone tell me how big a job it is to replace the thermostat in a 69 Merc 650 4 cyl? Engine does not warm up even to touch until running under load for several minutes and I'm pretty sure this affects performance. I re and re'd the carbs myself and though it wasn't fun, I got it done. How would thermostat re and re compare?
Thanks for any help.

 

[cr2k]

Re: Thermostat Replacement

Thermo is super easy. Just pull and replace new gasket also.

 

[Mi duckdown]

Re: Thermostat Replacement

If it's 1969 don't have t/stat

 

[jimmbo]

Re: Thermostat Replacement

If it's 1969 don't have t/stat

Doesn't need it

 

[Cariboo Milkman]

Re: Thermostat Replacement

Thanks everyone. Glad I don't have to go digging into the bowels of the engine again. I've got it running quite a bit better and hopefully with a bit of finetuning for altitude it should be good to go.

 

[Texasmark]

Re: Thermostat Replacement

Apparently Merc learned at their Florida Lake X testing ground back in that period, that stats could have a problem with corrosion in salt water and malfunctioning, causing severe engine damage, so they decided to not use one. Instead they went to their CDI 40kv Thunderbolt Ignition system figuring apparently that they would brute force the suckers to fire. Worked. In later years (speculation) they had EPA mandates and had to do what needed to be done to meet them...adding a stat must have been one.

HTH,
Mark