40454 overheats

[wannabewelder]

Hi Guys, researched the heck out of this one and I'm coming up nada.
Bought a 40 Evinrude and it had a bad point. I ordered points and condensers and in the mean time did a pressure test & reseal on the gearcase.
Got everything back together and it starts like a dream but the first thing I noticed was excessive back pressure out the exhaust and it doesn't sound like my '69. I then noticed there was no water coming out the exhaust and then threw a pyrometer on to confirm my suspicions.
The impeller is new, seals are good so I tore the head off since it is easy and I had a gasket. Was figuring it would have a hole in it and it did not. Compression 115/118 lbs.
Tore the exhaust cover off, cleaned & resealed, nothing remarkable. Changed base gasket while power head was off.
Not fixed.
Tore gearcase off, clamped a garden hose onto copper pipe and tried to flush. At one point water gushed out and then we did something and it stopped. Motor was in upwards tilt.
Loosened power head screws, tried again. Nothing leaked around base.
Pulled power head off. Turned water on and it shot out of lower unit.
Checked again, nothing plugged. Reinstall power head, turn hose on and check ports around cylinders heads gasket loosened.
Water now comes out. bolt everything back together, turn hose on and water shoots out exhaust. Bolt gearcase on......nothing. Engine is hot ansd runs like a bag of crap. Yesterday it idled fine
I checked online and cannot see where the thermostat should be. I thought however the water runs on a bypass which does not explain why this works intermittentl. Had this happen in a sunbird heater outlet once and needed a drill to break up sludge. The Evinrude is clean inside.
thanks in advance.......

 

[F_R]

Are you running that thing on a boat on the lake or in a bucket, or muffs, or what????

 

[boobie]

Edit......

 

[wannabewelder]

I am running in a bucket. I have 3 Evinrude 55's that all let a few drops out the exhaust and stays nice and cool on the pyrometer. This one likewise hits over 300F.
I also have 2, 1969 selectrics which mist out the exhaust and run cool in the same bucket.
This model will not take muffs over the screen, it needs an adapter.
The exhaust back pressure is blowing the water out of the 50 gallon barrel so I am not sure what to tackle first but it does need some back pressure from water to run correctly.
I just can't understand where all the back pressure is from. In a 4 stroke I would be looking at bad valves,timing etc.
Every Evinrude I have ever owned has had a thermostat bypass. Possibly there is a chunk rolling around in the head I can't find but would like to figure out where thermostat is before I pull it down again.
Thanks,again.

 

[Chinewalker]

How deep in the bucket are you? Water must be well over the water pump to prime. If it's only partially submerged, that may explain your intermittent pumping.

 

[racerone]

No point looking for a thermostat >----There in no thermostat on it.

 

[F_R]

Back pressure comes from the exhaust. Different motors have different methods of silencing the above water exhaust relief.

 

[wannabewelder]

How deep in the bucket are you? Water must be well over the water pump to prime. If it's only partially submerged, that may explain your intermittent pumping.

I run all my motors in the same bucket, it didn't pump any water on the motor itself. The intermittence was on the hose.

 

[wannabewelder]

Two more questions before I tear this thing down.....again. Has anybody had any issues with the T shaped woodruff keys, and were the stainless impeller plates absolutely flat? This plate has a bead rolled into it which definitely ewasnt done by hand and I crossed the #s and the ones on eBay don't seem to have this relief. It is not in an area contacted by the impeller and is off to the side. I had some spares here which were flat but they are earlier and bolt holes are different.
Short of pulling the gearcase and putting a drill on the shaft to check this I am at a loss. Screen is clear. At least on a car you can tap into fuel, oil pressure galleries.
I still maintain the head did not flow water on the garden hose hooked up to the copper pipe but this will alleviate which end of the motor to look at....

 

[wannabewelder]

Do these motors have PRV's?

 

[racerone]

PRV----Pressure relief valve ?------No not on that model.-----Are those plates showing that perhaps freezing water deformed them.-------Look closely at that possibility.

 

[wannabewelder]

The stainless plate below the impeller looks like it went through a bead roller. I would say that freezing water would more likely pop the housing which appears to be another alloy other than aluminum, without testing it i'd say perhaps zinc. I work with stainless all day long, def. not freezing. I think next week we will make adapters up and test the gearcase independently.
I also cleaned the screen today and raised the 50 gal bucket to no avail.
I would say however that if you have 115psi compression getting into the water jacket that there is no way the impeller will prime that runs maybe 30psi?? Which is why I checked the head gasket so we definitely need to isolate which end is up.

 

[hardwater fisherman]

If it looks something like this then it is from freezing.... I did not believe the first time I was told either.... Maybe check the housing because it also cracked on mine..

 

[wannabewelder]

If it looks something like this then it is from freezing.... I did not believe the first time I was told either.... Maybe check the housing because it also cracked on mine..

RIGHT ON!
Yes,THANK YOU, I saw exactly that, checked the P/N on ebay and they seem flat. What I did notice is the bend is outside the contact area. Thankyou. Next question is why it did not take out the housing? That stainless is strong stuff OR did somebody change the housing and miss this.....
I had a 70 year old mechanic look at this and put it back together.....

 

[wannabewelder]

Now, here is the conundrum. I cleaned out the contents of a marina 1949-1999. I have 2 Econoline vans full of NOS parts. I saw boxes of housings, boxes of impellers....not sure on the plates. Next issue is to find out WHERE they are in my shop as the cardex system used by the previous owner is all over the place.
So, we have here a truckload of Scott Attwater -McColloch,Chrysler, Eska, Elgin,OMC, Merc parts. 90% of this stuff I have never seen before. There may be 3-500 props. I did find Chrysler decals and in a few boxes some 56 era Johnson front panel transers and tiller grips. It is going to take about 2 years to catalog this crap less 1 impeller plate....

 

[wannabewelder]

this is the beast

 

[wannabewelder]

No point looking for a thermostat >----There in no thermostat on it.

SO the no thermostat was the start of the downfall of OMC not complying with EPA? I tore down another one of these blocks and thought I just missed it and my mind was playing idiot games with me....funny way to design something?

 

[racerone]

No------This design was a revival of an older ( early 1960's ) block engine.-----Done as a cost saver to keep market share stay competitive.-----The downfall started much later than your motor.