Thermostat removal - Did it right?

[Cucaracho]

Removed the Tstats, also the springs and round withe parts......just to check if it was still overheating, and I noticed that the tell tale lost strenght, before it was very strong and now very weak. I only tried it on a hose not on the lake.

Maybe I shouldnt have taken out everything just the thermostats, can I run it this way or should I open it again an place the springs and white plastic parts where they were?

Thanks for your help.

Jorge.

**** Johnson 110 hp 1989.

 

[Joe Reeves]

Re: Thermostat removal - Did it right?

Replace everything! And use new thermostats. Removing temperature controling components is just patch work, commonly referred to as a Mickey Mouse repair.

(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.

 

[Cucaracho]

Re: Thermostat removal - Did it right?

In fact the tstats are not more than a month old, but it kept overheating and I am just trying to rule out the tstats. Maybe I placed them worng or something. But I did not like the low pressure coming out of the peehole, before I removed the tstats the pressure was ok.

One side is significantly hotter than the other so I thougt one thermostat got stuck or blocked some way.

What do you think it might be?

 

[Joe Reeves]

Re: Thermostat removal - Did it right?

If you didn't replace the complete water pump assembly, do so.

On bank running hotter than the other may have faulty water deflectors. See the following.

(Water Deflectors)
(J. Reeves)

Water deflectors are actually lengths of 3/8" outside diameter rubber hose, installed between the top cylinder and any cylinder beneath it, and also between the bottom cylinder and the block. The purpose of the deflectors is to have the water follow a definite path around the cylinder walls. Unfortunately the deflectors between the cylinders will at times swell sideways due to either a previous bad overheating problem, or simply due to age and salt corrosion. This causes a water flow restriction which usually allows the water to cool sufficently at low rpms but not at the higher rpms.

This hose material can be purchased reasonably at any automotive parts type store if you care to make your own, or you can purchase individual deflectors at any Evinrude/Johnson dealership at a somewhat higher cost.

Removing and installing them can be a hassle at times, but not always. I use a sharply pointed scribe with about 1/4" of the tip bent at a right angle whereas I can reach in, jab the tip sideways into the rubber, then yank it out. It's necessary to clean the seating surfaces where the ruber contacts the block with a small rat tail file to eliminate salt deposits etc. When installing the new rubber deflector, coat the deflector and the metal surfaces with WD40 which will act as lubrication to allow it to go in as easily as possible.

Make sure that you insert something into that deflector area before cutting and installing the deflectors if you make your own so that you will be certain that they are the right length and also that they will be seated properly. Usually a very small amount will be left extending about the block sealing area..... simply cut the excess off with a single edge razor blade.

 

[Vic.S]

Re: Thermostat removal - Did it right?

But I did not like the low pressure coming out of the peehole, before I removed the tstats the pressure was ok

Once you have removed the thermostats and the pressure control valves there is nothing to make the pressure build up so the pressure at the telltale will be low.

 

[emdsapmgr]

Re: Thermostat removal - Did it right?

Without thermostats, the engine will run cold. Cold-running engines don't have normal combustion, so it may smoke more, get poorer fuel economy and may run/idle poorly. Running for long periods without stats will cause carbon to accumulate around the rings quicker and can lead to long-term powerhead failure. You need to put all the thermostat components back. When you do, make sure the two pinholes in the thermostat valve body are open. If one (or both) clog up, that side of the block will overheat.

 

[ezeke]

Re: Thermostat removal - Did it right?

The kit at this link has all the parts to do the job right: http://www.iboats.com/Sierra_18_367...0490526--**********.162156923--view_id.173543

 

[clanton]

Re: Thermostat removal - Did it right?

If the thermostats are good, the pressure releif valve is one of the problems, the valve will hang in the grommet and not open at high speed. The hole in the block for the grommet must be clean, use new grommet, valve must open and close very smooth, the black ones, sometimes need the edges trimed with a razor knife, because they were made too large.

 

[clanton]

Re: Thermostat removal - Did it right?

If you insist on removing the thermostats, just remove the guts and valve, reinstall the thermostat housing, this will restrict the water flow close to orignal.