Logo
FULL SITE MENU

1982 Johnson 90 V4

R

ripspear

New member
"I bought the motor a couple o

"I bought the motor a couple of months ago. After replacing one pack and one coil I had it running good and went to go out to the gulf and after about 20 minutes of running it overheated and shut down.... After taking of the cover I found one plug wire broken off and most of the electonics heat melted. I took the heads off and found some sand inside water jackets. All cylinders were very dark no metal. The diverters were out of round. The water pump appeared to be fairly new, no cracks, and the pee tube wasn't putting out any water. It took a couple of hours in 90 degree heat to cool off enough to touch.
Any Ideas, would the sand cause this? One of the plastic bypass plugs was melted out of round as well and someone had taken out the T-stats.
thanks
Mark"
 
"Sand will of course cause the

"Sand will of course cause the engine to overheat.

Obviously the engine had a overheating problem previously and the previous owner, some previous owner, rather than do the job properly and install a new complete water pump assembly, took the shorter route of removing the thermostats and unloaded the engine.

Be sure to tighten all the head bolts etc. Head bolt torque is 18 to 20 foot pounds in the following sequence.

9...10
5....6
1....2
4....3
8....7

(Thermostat Purpose)
(J. Reeves)

Many engines are considered high performance engines and demand a thermostat(s), and many smaller hp engines also require a thermostat for the following reason. The pistons actually distort/twist off round when running. The thermostat is required to keep the outer wall surrounding the steel cylinder, and the cylinder wall itself at a temperture to compensate for the distortion.

With the thermostat removed, the difference in temperture between the inside the cylinder and the water jacket quickly reaches a point whereas (in effect) you have a oblong piston running up and down a round cylinder, or vice versa. Bottom line is without the thermostat, the piston and cylinder wall could be damaged in a short period of time.

The thermostat in your car isn't there simply to have the heater function properly..... think about it.

When time permits, visit my store at: http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store

The overheat warning horn should have sounded long before the engine got hot enough to do any damage. Test the horn as follows.

Engine NOT running buit have the key in the ON position. Find the TAN overheat sensor wire protruding out of the cylinder head(s) and ground the wriing harness side of that TAN wire to the powerhead. The horn should sound. If it does not, find out why as that's the only warning you'll receive in the future to avoid a repeat of you present problem.

When time permits, visit my store at: http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store"
 
"Follow up questions
I have b

"Follow up questions
I have been cleaning out or flushing out the system... I put the hose in the port water outlet behind the t stats and it flows fine. I put the hose on the starboard side and it has pressure, is this normal or is there some old impella in there I need to did out. I also put the house in the two holes under the power head on the read on the mid section and had the same results.
also are the t-stats suppose to face the block or the rear.
thanks
mark"
 
"If You want to 'flush&#39

"If You want to 'flush' the system, drop the lower unit and attach a hose to the water tube.
However I suggest You pull both heads and replace the deflectors as well.
The thermo elements of the thermostats are supposed to face the rear of the engine, catching the hot water coming from the heads.
After what seems to be a major melt down, I would suggest to replace both thermostats and pressure valves springs."
 
"Ok, thanks for the good infor

"Ok, thanks for the good information. I just want to be sure we are on the same page. The thermo element is the spring? and when you saye face the rear you are saying that the spring side is suppose to be inside the exust housing side? What about when I put the hose in the holes in the exhust side where the water goes out of the t stats and it flows free on one side but a little restricted on the other?
you guys are great.
Mark"
 
"This pic should clear the &#3

"This pic should clear the 'confusion'. Replace pressure valve springs #34, to be sure they have the same opening pressure. Would not be surprised if valves #27 have melted and needs replacement as well.
218077.gif
"
 
"The pic helped....I put every

"The pic helped....I put everything back together and the motor started up, got hot shut it off. Pulled the two hoses off each head started up again and no water. do I need to pull lower unit off and put the hose directly into the tube? Could I have a blockage in there someplace.
thanks
Mark"
 
Pull the lower unit and test d

Pull the lower unit and test directly on the water tube. ( You may even run the engine). Did You change deflectors?
Be aware of the seal #30. If that is burned/damaged exhaust will get into the pump!!
 
Back
Top