70 Johnson- Thermostat removed

[garycunn]

A mechanic removed my thermostat from my 70hp Johnson after the horn activated for<br />no obvious reason, he also disconnected the<br />horn. Mechanic said thermostat not needed, just another area to clog and restrict water.<br />I have been running the motor for three summers in Maine coastal waters and all seems well. It does stall sometimes at low<br />rpms could this be why?<br />Thanks in advance this message board is very informative.

 

[alcan]

Re: 70 Johnson- Thermostat removed

Hello Liveliner<br />I would make the proper repairs. I do like your mechanic's attitude. When something breaks throw it over board. Sounds like a good way to save money. Good luck have fun!

 

[Fouled Plug]

Re: 70 Johnson- Thermostat removed

Is this mechanic your brother in law? I would be very nervous running without a warning horn. And the thermostat has an important function, to regulate the flow of cooling water to the engine. At best, you will never have a consistent operating temp. I doubt it is affecting your low RPM operation, though. I would consider finding a new wrench!

 

[evin300]

Re: 70 Johnson- Thermostat removed

Engine is running to cool w/o t-stat, this equals lots of carbon. re connect horn and fix the real problem (if any) replace stat, then replace mechanic. Then de-carbonize this coked up motor. Good Luck!

 

[petryshyn]

Re: 70 Johnson- Thermostat removed

For gods sake man, reconnect that horn! Its you first and last warning, and even that can be too late!!<br />About 90% of engine wear occurs during warm-up. You may not see immediate affects from running without a thermostat, but pull it down in a couple years and compare engine wear. At idle, the engine doesn't produce much heat, so we need to restrict coolant to bring temp up to a safe high.(promoting longevity) Even 140F is low, but we are limited, do to the system being unpressurized. I've put thermostats in engines that weren't speced for them, to prevent fouling at idle. Engines run the longest when they are at a safe high temp. Carbon will form on the piston skirts and eventually score the cylinders if run cold. If the OEM puts them in, there needed.....The absence of them may go undetected if you run WOT all day, but if you idle alot....beware.<br /><br />Oh, by the way, next time it stalls, pull the plugs......are they fouled? If so, your heading in the right direction.<br /><br />As FP says, find a new wrench!! He probably removed his EGR valve from his car as well....LOL<br /><br /><br />Just my humbble opinion.....<br /> <br /><br />Sorry Evin300, didn't see you!!!!!!

 

[evin300]

Re: 70 Johnson- Thermostat removed

No Prob Shematic! I enjoyed your thorough responce!

 

[johnyrude]

Re: 70 Johnson- Thermostat removed

Liveliner- If this is your mech. usual way of fixing problems he should be flipping burgs instead. Now, if your 70 HP is a 1986 thru 1994 have is dude look at OMC service Bul# 2276 under the powerhead section. It describes the relocation of the water indicator outlet to prevent trapped air in the block. If he does not have it avail. take your engine to someone that does before you fry it or carbon the heck out of it.