1990 Johnson V6 T-Stat Conversion

[27E_20]

There are several threads related to this topic here on iboats, but none are specific to my question. Most threads list the part numbers needed and the fact that doing this "upgrade" gets rid of some unnecessary hoses as well as eliminating the water control valve.

I now have all of the parts and am ready to begin. What I was hoping to find out is: Based on the attached photo, where does the hose with the blue line get re-routed to?

I understand that the rest of the hoses pretty much get thrown away, but Im not sure about the one that comes from the base of the engine. Before it lands at the water control valve, it tees off to the pressure gauge at the steering wheel.

So... if the water control valve goes away, where does it need to go?

 

[Faztbullet]

Re: 1990 Johnson V6 T-Stat Conversion

Here ya go...sorry it too so long had to dig it out of pic files//

 

[27E_20]

Re: 1990 Johnson V6 T-Stat Conversion

Man, thanks Faztbullet- thats just what I needed! What is the secret to disconnect the throttle linkage from the water control valve? Looks like it just a plastic bushing or something. I was expecting a retaining ring.

Also, what is the hose for that is connected to the tell tale on one end and with the other just laying in the bottom of the motor? (Far left of your pic)

 

[27E_20]

Re: 1990 Johnson V6 T-Stat Conversion

Ah, never mind. Just pulls right off.

Still would like to know what that hose is for.

 

[boobie]

Re: 1990 Johnson V6 T-Stat Conversion

It was a syphon for any water that got in your lower motor cover.

 

[27E_20]

Re: 1990 Johnson V6 T-Stat Conversion

Thanks boobie. Now Im curious... Which thermostats do I keep? From reading this post, it sounds like I should keep the old housings, just switch out the vernatherms. If so, can I keep the existing seats? Heres what ezeke said:

The later replacement covers for the thermostats will not have hose outlets. Part numbers will be 333967.

The later covers do not use the diaphragm, they use a gasket # 329830 instead.

You will need large springs, part #336765 or 0333858.

You should use the new thermostat assemblies, part # 434137.

You will need to re-route the tell-tale hose.

Keep the old thermostat housing if they are the white ones. The extended noses will fit the new assemblies and they provide better circulation. If you find that you have a marginal cooling problem, you can just switch the noses and get more water through the cooling passages.

Test the old vernatherms. If they are still functioning, keep them for spares.

 

[boobie]

Re: 1990 Johnson V6 T-Stat Conversion

Go to shop.evinrude.com and look up a 1993 mtr of your horse power and you'll find the part numbers.

 

[Faztbullet]

Re: 1990 Johnson V6 T-Stat Conversion

You will need the following:
(2) 0333858 springs
(2) 0333967 covers
(2) 0329830gaskets
(2) 0394409 t-stat assy or
(2) 0394411 veratherms 140? not the 105? some aftermarkets offer
This makes both cylinder banks work independently of each other just like the 3 cylinder 70 the parts list is from.The 93 parts wont work....

 

[27E_20]

Re: 1990 Johnson V6 T-Stat Conversion

Thanks Faztbullet. Ive got all that stuff, just wondering if I should worry about changing the seats.

ezeke again:

Some of the old seats with the metal holder failed and needed replacement. The new ones don't have the metal ring. Mine never failed, so I still use them, with the black thermostats.

 

[Faztbullet]

Re: 1990 Johnson V6 T-Stat Conversion

If they are intact leave em alone as it takes a press to put the metal retainer in (new head gaskets required) and had little luck trying to roll one out/in.

 

[rapishorrid]

Re: 1990 Johnson V6 T-Stat Conversion

If they are intact leave em alone as it takes a press to put the metal retainer in (new head gaskets required) and had little luck trying to roll one out/in.

I'm doing the water control valve delete on my '90 200hp and am looking to change out the thermostat seats with the updated 1 piece seats (P/N 0336416) from the service bulletin linked below. Will I be able to get the old 2 piece seats with the metal cup (P/N 0330273 & 0320880) out and these new seats in without a press or new head gasket?

Old thread - but not many people are talking in depth about these motors any more...

 

[GA_Boater]

If you don't start a new thread, there is no discussion to be had. Most members don't read the old threads, Read the Help Tip on top of the page and start a new thread. That's how it works here.

Closed.