Is there a thermostat on this thing?

[Betterthannothin]

1986-87 merc. 75hp..... Is there a thermostat? If so where. Thanks in advance.

 

[Chris1956]

Re: Is there a thermostat on this thing?

I doubt it has a thermostat. Few Merc inline motors of that vintage did. The parts list on Crowleymarine.com will tell you for sure.

 

[Faztbullet]

Re: Is there a thermostat on this thing?

If its the 4 cylinder 75hp it has no t-stat.................

 

[Betterthannothin]

Re: Is there a thermostat on this thing?

I didn't think so but I thought I should ask the experts......Thanks!

 

[Texasmark]

Re: Is there a thermostat on this thing?

Back in those days, Merc thought their 40kv spark would do the job for them I guess.....just like they thought their carbon steel shafts would hold up to salt water. Either they thought that they were saving a buck, or it was just something to fail with corrosion and salt water and all and I totally agree with that. Butttt those problems can be protected against.

Don't know why it took them so long to follow OMC with stats, SS drive/prop shafts and all....I think the OMC SST beat Merc with a SS prop also....don't remember for sure.

Welllll they finally got the message and installed stats; don't remember the date but it was after '84 as I had an 85 of that year model and it didn't have one.

Now, the funny part. I bought a '74-'75 60 hp 3 cyl Rude that had a stat and guess what.... the only thing that ever failed on that engine was the stat and with no warning horn, one day at WOT it just locked up......$1000 later and a lot of work, it was back in service.

My 2c,

Mark

 

[Alumarine]

Re: Is there a thermostat on this thing?

Just curious. Without a thermostat how do they regulate the temperature?

 

[Faztbullet]

Re: Is there a thermostat on this thing?

No Mercury/Mariner (crossflow) inline 4 or 6 cylinder has ever had a t-stat. The inlines cool by volume not by pressure. Thats the reason a water pressure guage reads low on a inline engine, 0-3 psi at idle and 10-14psi @WOT. The water is restricted in the adapter plate and block to maintain a good running temp as water fills cylinder jug area first then thru exhaust plate and back into adapter plate.

 

[Alumarine]

Re: Is there a thermostat on this thing?

Thanks for the explanation.

No Mercury/Mariner (crossflow) inline 4 or 6 cylinder has ever had a t-stat. The inlines cool by volume not by pressure. Thats the reason a water pressure guage reads low on a inline engine, 0-3 psi at idle and 10-14psi @WOT. The water is restricted in the adapter plate and block to maintain a good running temp as water fills cylinder jug area first then thru exhaust plate and back into adapter plate.