where would I find Johnson 90 hp V4 thermostat to check whether it is stuck closed or open?

[ib18]

where would I find Johnson 90 hp V4 thermostat to check whether it is stuck closed or open?

where would I find Johnson 90 hp V4 thermostat to check whether it is stuck open? J90MLCNB
picture is showing the pipe under the cylinders. Do I just open the clamps and unscrew the nut in the picture?

 

[racerone]

There are 2 thermostats and 2 poppit valves in that housing.-----3 bolts need to come out.-------Good luck with inspecting that on your motor.

 

[boobie]

What's the problem with the motor ?? overheat ?? overcool ??

 

[emdsapmgr]

There at two more bolts at each end of the housing. The pictured one is in the middle. Not too bad a job on a flatback crossflow engine. Are you working from a factory service manual or exploded parts diagram?

 

[ib18]

Thanks for your first class super fast responses. I cold started my Johnson 90 hp first time today after it died in October while fishing.
The water coming out of the pee hole was warm, hot, normal and hot again. I tried touching the powerhead of the 4 cylinders and they are hot but not burning hands yet. My 2 guess are (1) water impeller is bad (2) thermostat is stuck closed.

2 Thermostats - #78, gasket - #33 (do I need to buy this or I can use the old gasket?)

yes, I am working from the parts diagram

 

[Bosunsmate]

You definitely need to change the impeller.
If that doesnt fix it then you need to check thermostats then water deflectors and blocked cooling passages in that order.
Seems to idle well, but as you say you need to figure out the heat issue.

 

[daselbee]

That would be an '82 model....I swear I would be tempted to inspect the deflectors. Might just stop a serious problem with overheat.

This is a very strong recommendation. Just depends how the cylinder head bolts are...frozen or removable. Big IF on that motor.

 

[racerone]

I am thinking that broken / siezed bolts will be an issue on that motor.

 

[daselbee]

I am thinking that broken / siezed bolts will be an issue on that motor.

OK...that's what I said.

Which is worse? Broken head bolts or a toasted cylinder from a broken ring? He will break the head bolts rebuilding the toasted cylinder...:joyous:

 

[V153]

Fwiw I've broken every other bolt takin these things apart. But never a head bolt?

Start soakin the chit in PB Blaster immediately. Wait awhile. Rinse and repeat. Then wait some more.

 

[Bosunsmate]

Fwiw I've broken every other bolt takin these things apart. But never a head bolt?

Start soakin the chit in PB Blaster immediately. Wait awhile. Rinse and repeat. Then wait some more.

I havent struggled on them either but ive only worked on one of them. Was a saltie its whole life.
Even the exhaust bolts came out good, but the powerhead to base ones tested my resolve especially the ridiculously little ones at the rear

 

[daselbee]

I want you to read thru this complete posting. It applies to you and your motor.
Might svae you some serious money.

http://forums.iboats.com/forum/engi...nson-evinrude-outboards/9145634-0-compression

 

[ib18]

yes, thanks for all your input. I just finished changing the lower unit oil and found water in the lower unit. I am still in the process of changing impeller. But, need a flex shaft slotted screwdriver to take out the slotted screw that engage the shift arm and the gear shaft to the lower unit so I can drop the lower unit. Hopefully, I don't need to worry about the thermostats or water deflectors. I certainly don't want the motor to overheat. All 4 cylinders have 110 psi compressions after my motor would not start last October.

http://forums.iboats.com/forum/engi...n-remove-the-shaft-linkage-to-drop-lower-unit

 

[racerone]

So your gearcase sat for 5 months ( possibly longer ) with the gearcase 1/2 full of water ?----Not worried about the gears and the bearings ?

 

[ib18]

So your gearcase sat for 5 months ( possibly longer ) with the gearcase 1/2 full of water ?----Not worried about the gears and the bearings ?

yes, I do worry about it which is why I why just replaced with SAE 80-90 instead of SAE 90 and reused old plastic O-rings (just got the new o-rings). My approach is to address my hot peeing water first, and then I will test run the motor to see whether I have any damage or leak in the lower unit.

I have to check the gear box after my first or second water test of the motor, so I will seal it or rebuild it later. I will place order of SAE90 soon.