1999 Johnson 150 Ocean Pro Cooling Question

[woodycooper]

Re: 1999 Johnson 150 Ocean Pro Cooling Question



running at 1500 should put more pressure behind the water flow.... at idle sometimes my motor runs a little warm..I give it rpms and the temps fall...because i am getting more flow.....

you should only use the exact socket in SIX POINT ONLY! that fits that plastic hex on the t-stat housing.

that housing comes off and it has an o-ring that seals the water, inside it is a spring that forces the thermostat itslef against a rubber seal in the head... at low pressure the t-stats holds back and seals water from entering the head...once it gets warm enough( about 145 degrees) the t-stat opens and allows some water into the head...

the outer spring that pushes on the t-stat body is for allowing the whole t-stat to come off the seal and allow a LOT more water to flow into the head!! its like a dual acting device.....

some guys have used gasket sealant on the threads and o-ring of the housing with the nut on it....so a warm motor might help you unscrew it....I have had one break apart.....soo...never do it in cold weather!! and slow steady force, no blows with a hammer!! and the warmer the better..heck even use a blow dryer if you have to!!

bob

I seem to rember that the socket you need is something like 13/16 or something odd. I had to buy one special because it's slightly bigger than my biggest socket, 18mm or 3/4. The first time I opened mine I needed a cheater bar, and from then on I just spray some lubricant on the threads. Be careful, they are fine threads and easy to cross thread. Thermostats pop out with needle nose plyers. I replaced mine two years ago and they are had to replace them recently as they were stuck closed. If you don't flush after every use in salt water they'll get eaten up fast.

I'm in a similar situation. Checked fuel restriction, rebuilt fuel pump, replaced both overheat sensors, thermostats, and did an acid flush. Just got finished replacing the water pump and various exhaust gaskets and now I get the fun part of putting the lower unit back on and reconnecting the shift linkage. Last time I did that it was a PITA!

My real question is how to measure the temp. Someone on this thread said to aim the IF gun at the top of the cylinder block. The SELOC shop manual says to try to measure inside the overheat sensor pocket, which is significantly hotter. I've been going by that measure and have been thinking the engine is running too hot, but if the measure is to be taken from the block, then it's OK. The overheat sensors go off at about 200 so it makes a certain amount of sense that they would be adjusted for the hotter temp. When the horn goes off the outside of the block doesn't reach 150F or slightly over. Make sense?

 

[saltchuckmatt]

I seem to rember that the socket you need is something like 13/16 or something odd. I had to buy one special because it's slightly bigger than my biggest socket, 18mm or 3/4. The first time I opened mine I needed a cheater bar, and from then on I just spray some lubricant on the threads. Be careful, they are fine threads and easy to cross thread. Thermostats pop out with needle nose plyers. I replaced mine two years ago and they are had to replace them recently as they were stuck closed. If you don't flush after every use in salt water they'll get eaten up fast.

I'm in a similar situation. Checked fuel restriction, rebuilt fuel pump, replaced both overheat sensors, thermostats, and did an acid flush. Just got finished replacing the water pump and various exhaust gaskets and now I get the fun part of putting the lower unit back on and reconnecting the shift linkage. Last time I did that it was a PITA!

My real question is how to measure the temp. Someone on this thread said to aim the IF gun at the top of the cylinder block. The SELOC shop manual says to try to measure inside the overheat sensor pocket, which is significantly hotter. I've been going by that measure and have been thinking the engine is running too hot, but if the measure is to be taken from the block, then it's OK. The overheat sensors go off at about 200 so it makes a certain amount of sense that they would be adjusted for the hotter temp. When the horn goes off the outside of the block doesn't reach 150F or slightly over. Make sense?

Tough to answer....book says one thing but people do it all different ways.

Water passages are all over the place. When the water comes up from the pump it goes through some of the engine but a bypass let's it come out the tell tale. Tell tale only tells you that the pump is pumping. Once the motor gets hot, thermos open.... and cools additional things like the heads. Really, you should shoot all around and your bound to get different readings.

If for some reason you get areas that are excessively hot, than it usually points to some kind of plug or choke point. Water takes the path of least resistance so flow is compounded.

 

[McGR]

Yes the hex on the thermostat covers is 13/16. 13/16 spark plug sockets work well for this.

 

[saltchuckmatt]

Yes the hex on the thermostat covers is 13/16. 13/16 spark plug sockets work well for this.

Mine had two options, smaller one and the 13/16 one.

 

[woodycooper]

Tough to answer....book says one thing but people do it all different ways.

Water passages are all over the place. When the water comes up from the pump it goes through some of the engine but a bypass let's it come out the tell tale. Tell tale only tells you that the pump is pumping. Once the motor gets hot, thermos open.... and cools additional things like the heads. Really, you should shoot all around and your bound to get different readings.

If for some reason you get areas that are excessively hot, than it usually points to some kind of plug or choke point. Water takes the path of least resistance so flow is compounded.

I hear you about the all different places thing. The sensor pockets are almost an inch deep into the cylinder head and therefore closer to the combustion. Actually it's between two cylinders. Either way, it reads the same on both sides, higher in the pocket than the outside of the block / clylinder head. On my motor, the telltale only lets some water through and the thermostats pop out under a certain amount of pressure. I tested this with a garden hose hooked to the flush adapter with the lower unit removed. By plugging the intake tube water pushes out the thermostats and exits from the exhaust. The lower unit is off because I replaced the water pump thinking that there wasn't sufficient pressure to pop out the valves.

 

[saltchuckmatt]

I hear you about the all different places thing. The sensor pockets are almost an inch deep into the cylinder head and therefore closer to the combustion. Actually it's between two cylinders. Either way, it reads the same on both sides, higher in the pocket than the outside of the block / clylinder head. On my motor, the telltale only lets some water through and the thermostats pop out under a certain amount of pressure. I tested this with a garden hose hooked to the flush adapter with the lower unit removed. By plugging the intake tube water pushes out the thermostats and exits from the exhaust. The lower unit is off because I replaced the water pump thinking that there wasn't sufficient pressure to pop out the valves.

So before all this was your overheat alarm going off?

 

[flyingscott]

How about you start your own thread and Not open a 10 yr old one