Logo
FULL SITE MENU

1995 Evinrude 20hp overheated

C

curtmacd

New member
I bought this boat and motor used. I decided to replace the water pump before I started the motor, just as a precaution and not knowing it's condition. Took it to the lake today and it started on the second pull and ran perfect. Idled good. I pulled away from the ramp and accelerated the motor and it started missing. I looked at the tell tell for the water and there was no water coming out, I then noticed a hot odor coming from the motor so I shut it down. I used the trolling motor to get me back to the ramp. I pulled the lower unit to examine the water pump assy I had replaced and everything looked like new. The impeller was engaged with the shaft keeper and everything looked just like I had installed it. There is a possibility that the water tube to the engine block was not inserted in the rubber bushing at the pump. It's possible that in missed it when I stabbed the lower unit back on, but I honestly don't think so.
So I have inspected everything and put it back together. The engine still has good compression, but it acts like it won't fire now? I'm replacing the spark plugs in the morning and going to give it another try.
#1 can the temp sensor go bad and keep it from starting?
#2 I think I should also replace the thermostat, would you agree?
What else would keep it from firing? Especially considering it ran so well before it overheated.

All help is appreciated!
 
If it got really hot wiring might have melted and shorted to ground.----Model # ?----Electric start , remote control ?
 
racerone said:
If it got really hot wiring might have melted and shorted to ground.----Model # ?----Electric start , remote control ?
Click to expand...

It's a tiller motor model E20CRLEOR non electric start. It did melt a little bit of the rubber sleeve that the wiring is inside, but no damage to the wires at all. I removed the burnt part and inspected the wires closely. Also, due to the heat and lack of water flow, the plastic fitting that the tell tell water line is hooked to, melted and pushed out of the threads. I will chase that with a tap and replace that piece. Will the temp sensor keep it from starting once it gets that hot? Or, is it possible that the electronic module overheated and needs replacing? I'll know more this evening after I explore a bit more.
 
Racerone has you on the right track. Hindsight is 20/20, but with an unknown used engine you definitely did one thing correct by replacing the water pump. I'm not throwing stones here, but next time I'd suggest you go a step further and tank test the engine at home before hitting the water. This gives you the chance to observe everything in a controlled environment with tools on hand to make any needed adjustments and verify it's good. I've learned that the hard way myself and now any used engine gets a full once-over before I hit the water.

KJ
 
racerone said:
I think a compression test is the absolute first thing to do.---Need to post actual numbers.
Click to expand...
The compression read 75psi top cylinder, 70psi bottom. Plugs we’re pretty clean. Not sure what the compression was before it overheated? It ran very smooth and started on the second or third pull. I’m thinking the compression is low, but is it too low to run decent?
 
kevinj said:
Racerone has you on the right track. Hindsight is 20/20, but with an unknown used engine you definitely did one thing correct by replacing the water pump. I'm not throwing stones here, but next time I'd suggest you go a step further and tank test the engine at home before hitting the water. This gives you the chance to observe everything in a controlled environment with tools on hand to make any needed adjustments and verify it's good. I've learned that the hard way myself and now any used engine gets a full once-over before I hit the water.

KJ
Click to expand...
I agree. My question now, is 70-75psi compression considered too low to continue without considering rebuilding?
Also, I'm not certain what "Racerone" is specifically wanting me to look at when I remove the head or intake by-pass cover?
 
Damaged parts.-----I think the damage may be obvious.-------A good cylinder would show a nice crosshatch finish.-----Piston / rings would not have any smeared aluminum.
 
racerone said:
Damaged parts.-----I think the damage may be obvious.-------A good cylinder would show a nice crosshatch finish.-----Piston / rings would not have any smeared aluminum.
Click to expand...
I'll take it apart this weekend and see what's happening. The rebuild kit is around $400. I'll clean up the cylinders and see how they measure out, before ordering parts. I'll feel better knowing what I have, this motor is too nice to toss. Thank you for your advise, I've never built an outboard before, this will be the first but it looks pretty straight forward.
 
curtmacd said:
I agree. My question now, is 70-75psi compression considered too low to continue without considering rebuilding?
Also, I'm not certain what "Racerone" is specifically wanting me to look at when I remove the head or intake by-pass cover?
Click to expand...

My 1988 reads 130-135psi in each. 75 is pretty s$hity. Without addressing whatever it is that is causing the lower compression you will not be happy with its performance IF it even starts.
 
curtmacd said:
I agree. My question now, is 70-75psi compression considered too low to continue without considering rebuilding?
Also, I'm not certain what "Racerone" is specifically wanting me to look at when I remove the head or intake by-pass cover?
Click to expand...
Yes, 70-75PSI is too low on this motor and it will not run right.

You possibly got it hot enough to warp the head which is the reason for removing and inspecting. You'll be looking for score marks in the cylinder walls or bits of melted aluminum smeared on the top of the piston or head if there was internal damage. Also, look at your head gasket for signs of water intrusion that would result from a warped head. With the head off and all gasket material removed you can put a straight edge on the mating surface to see if there are obvious gaps. You can also put a large sheet of 220 sand paper on a piece of glass and LIGHTLY sand the mating surface. Inspect frequently to see if there are high spots that show up. If there are, you might be able to completely resurface the head this way if it's not too terrible, but a new head could be possible.

If all is good and the head resurfaces well then a new head gasket and a new thermostat might get you back where you should be.

KJ
 
kevinj said:
Yes, 70-75PSI is too low on this motor and it will not run right.

You possibly got it hot enough to warp the head which is the reason for removing and inspecting. You'll be looking for score marks in the cylinder walls or bits of melted aluminum smeared on the top of the piston or head if there was internal damage. Also, look at your head gasket for signs of water intrusion that would result from a warped head. With the head off and all gasket material removed you can put a straight edge on the mating surface to see if there are obvious gaps. You can also put a large sheet of 220 sand paper on a piece of glass and LIGHTLY sand the mating surface. Inspect frequently to see if there are high spots that show up. If there are, you might be able to completely resurface the head this way if it's not too terrible, but a new head could be possible.

If all is good and the head resurfaces well then a new head gasket and a new thermostat might get you back where you should be.

KJ
Click to expand...
Thanks. I'll pull the head first and see if I see something obvious. I'll also pull the intake by-pass cover and examine the cylinder walls. I'll know more by this weekend. Thanks to all for your help. I'll report back.
 
curtmacd said:
Thanks. I'll pull the head first and see if I see something obvious. I'll also pull the intake by-pass cover and examine the cylinder walls. I'll know more by this weekend. Thanks to all for your help. I'll report back.
Click to expand...

Don't forget a spray can of fogging oil. Once you pull the head and bypass cover you'll have steel components (cylinder walls, rods, crank) exposed to the humid air. Give all those surfaces a good coating of fogging oil while it's open and if you're waiting on parts.

KJ
 
kevinj said:
Don't forget a spray can of fogging oil. Once you pull the head and bypass cover you'll have steel components (cylinder walls, rods, crank) exposed to the humid air. Give all those surfaces a good coating of fogging oil while it's open and if you're waiting on parts.

KJ
Click to expand...
Will do, I have some on hand.
I'm going to approach the head angle first and see if there is a warpage issue or gasket issue. On another note, I put a new set of NGK plugs in it this morning and pulled the rope twice and it fired right up. Sounded really smooth and idled & accelerated perfect. Of course with the water clamp on it. Still, the 75psi compression has me really concerned, so the head is definitely coming off. Hopefully I will find an issue with the head or gasket and see nice cylinder walls.
I'm a retired lifelong ASE mechanic and build engines, transmissions.....you name it. BUT, I have never rebuilt an outboard motor! Looks like fun, but I really cherish the advise from outboard pros!! I'm in Northwest Montana, sitting on Flathead lake. I'm sure I can find some outboards to pick up reasonably and tinker with, now that I'm retired. I have tons of tools and an ideal heated shop area. Thanks again! I will keep you posted.
 
I wanted to make sure I had water flow out the telltale before I removed the head and began my inspection. I put the water clamp on and it started on the second pull, ran smooth BUT no water coming out of the telltale still! I thought perhaps I had not installed the water tube in the rubber pump bushing the first time, but I made absolutely sure the tube was inserted correctly the second time. Apparently, there is a water block somewhere? The telltale rubber tube is clear and all I get is a little bit of steam when it ran for about 30 seconds. I didn't let it run long enough to get hot and do more damage. Getting a little miffed now as to why it won't pick up water? It must be something in the water jacket blocking flow. I'll test the thermostat when I have it out and make sure it's opening in a pan of water. I'll know more and get some pics when I pull the head later today. I'm absolutely sure the water pump is installed correctly. I even forced compressed air up the tube when I had the lower unit off and felt air come out the telltale tube fitting, without the rubber hose on? I'd like to do my best to resolve the water flow issue before I pull the head, but that doesn't seem probable at this point.
 
Perhaps you have a blown head gasket.-----Causes overheating .----Causes low compression numbers.-----Open the tool box and start inspection !!
 
racerone said:
Perhaps you have a blown head gasket.-----Causes overheating .----Causes low compression numbers.-----Open the tool box and start inspection !!
Click to expand...
Bingo....... a few of the head bolts were barely over finger tight! Obviously the gasket shows it's been compromised. The thermostat is also frozen solid "closed". And bent? Probably from heat. The good news is, the cylinders look to be in awesome condition. Good cross hatching and no visible scoring, other than what you would expect. The pistons look good. I threw a straight edge across the head and found .002 at the most warpage.
I'll clean it all up and surface the head lightly and put it back together. I can't believe it would even run with the head that loose. Of the three rubber water jacket inserts, the top one was fine, the lower left was deteriorated but still in place and the lower right one was stuck about 1/4' through the head gasket.

What is the head torque spec?IMG_4228.jpgIMG_4228.jpgIMG_4239.jpgIMG_4238.jpg
 
The thermostat is stuck OPEN.----See that all the time !-----Resurface the cylinder head to make it flat.-----Install new head gasket.
 
Have all my parts, now going back together. The head came out very nice, used a thick glass surface and 220 grit paper. It took about an hour to get it where I wanted it, but it is FLAT and smooth. I flattened the cover side as well. Super curious to see how much the compression has improved.
IMG_4242.jpg
 
yes indeed, excellent job getting the head clean. 0.002" warp isn't bad for a head that old. With your excellent cleaning job and a properly torqued new gasket I'll bet you'll see a big improvement.
 
racerone said:
Good job on the head.
Click to expand...
Going back together with it tomorrow, but I still have a concern. I need to make absolutely certain I have water circulation immediately. I have yet to see water coming out of the telltale tube! Before, with the motor running at 75psi compression and the water clamp placed on the lower unit, I STILL was not getting flow. That's the first thing I will be looking for. I know the pump is new and installed correctly.
 
kevinj said:
yes indeed, excellent job getting the head clean. 0.002" warp isn't bad for a head that old. With your excellent cleaning job and a properly torqued new gasket I'll bet you'll see a big improvement.
Click to expand...

What is the trick to installing the new rubber water deflectors back in the cylinder block?? Man, I've used Vaseline and oil and so far, can't seem to get them to go in all the way?
 
Finally was able to install the rubber water deflectors with the help of a 90 degree pic. Wrapped it up, fired it up and it runs good. Water is finally circulating and the motor ran cool. Pulled the plugs and checked compression again. 105psi in both cylinders. It blew a little smoke at first, I'm sure from the fogging oil. So I'm going to give it the lake test as soon as the weather cooperates. From 75 to 105psi compression aint bad, not perfect. Maybe with some run time with the head issue fixed, I may get a few more psi on the next check? At least both cylinders are even.
Thanks for all the advise racerone & kevinj!!
 
Back
Top