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Not Again! Seized 1987 Evinrude 60HP

K

KSH

Member
I have a 1987 Evinrude 60HP (E60TLCUC) which I have just rebuilt the powerhead. The reason for this was that I had scoring and melted rings on pistons 2 and 3. I believe this was due to a blocked jets on the corresponding carbs. I had the cylinders bored oversized 0.03" and have put the powerhead back together. I have cleaned the carbs and checked the timing using Joe Reeves WOT method.

I started the motor in a bucket yesterday. Running 25:1. I had a few wiring issues causing an alarm but I attributed this to connecting the 3 PIN plug from the VRO fuel pump, which has been capped and I now running pre-mix so this plug should not have been connected.

Today I ran the boat in the water and I think I have caused it to seize again. I first ran the motor on the trailer in idle for 15 minutes before taking the boat of the trailer. I then put it in gear took it off the trailer and drove around for around another 10 minutes, did not get above 1500rpm and temperature was sitting at 60oC. The motor then stalled and the starter motor would not start the motor back up. We tested to see if this is an electrical issue and determined it was not. We tried to spin the flywheel and it was very tight to turn hand. It would move smoothly after I rebuilt the powerhead.

Trying to get some direction of what I may have missed before I start tearing it apart again.


 
I assume that the two affected cylinders were bored over-sized .030 (thirty thousands) and the remaining two were simply deglazed. Also assuming that you installed new piston rings on all pistons. You did have a service manual?

The carburetors..... It is mandatory that "all" carburetors be thoroughly cleaned and rebuilt when doing a powerhead overhaul as they are highly subject to jet fouling. Did you remove and thoroughly clean "all" of the high speed jets that are located in the bottom center of the carburetor float chambers? If not, do so.

Your first clue that something was drastically wrong was the engine not being able to exceed 1500 rpm... time to shut it down and begin trouble shooting.

However, you may be lucky... drop the lower unit as "Kim" suggests to determine if the seizing is with the powerhead or the lower unit. If with the powerhead, start with removing the cylinder heads to reinspect the pistons etc.

NOTE: If portions of a broken piston ring be becomes embedded in the cylinder head and cannot be removed, replace the cylinder head. To reuse a cylinder head in that condition will result in that portion of embedded steel to glow like a model airplane glow plug which in turn will result in pre-ignition, effectively causing the aluminum piston to melt down.
 
You should have the 3-3/16 bore engine. Did the shop that bored it modify the bridge ports? OMC had some problems with this as if engine overheated the bridge would expand and scuff exhaust side of piston. When I bore one I sand down the bridge about a .001 with dremel tool. One of the "in field" fixes was installing the 3 vane impeller, as it moved more water at less pressure. If this has happened check the exhaust side of block passages for restrictions/stoppages.This will be the several holes cast into block as exhaust cover is just that a cover,should be 3 hole if I remember correctly. Don't worry about compression test as it could show fine and exhaust side of piston be totally bad/damaged.
 
Last edited:
racerone said:
What was your procedure for aligning rod caps / tightening connecting rod bolts.
Click to expand...

To align the rod caps, I used a micro screw driver (I didn't have a dental pick) to run across the break line and checked that it did not catch on any of the corners of the rod caps. The manual states that alignment is required on 3 of the 4 corners. I then torqued new connecting rod bolts to specs.
 
faztbullet said:
You should have the 3-3/16 bore engine. Did the shop that bored it modify the bridge ports? OMC had some problems with this as if engine overheated the bridge would expand and scuff exhaust side of piston. When I bore one I sand down the bridge about a .001 with dremel tool. One of the "in field" fixes was installing the 3 vane impeller, as it moved more water at less pressure. If this has happened check the exhaust side of block passages for restrictions/stoppages.This will be the several holes cast into block as exhaust cover is just that a cover,should be 3 hole if I remember correctly. Don't worry about compression test as it could show fine and exhaust side of piston be totally bad/damaged.
Click to expand...

These motors are the 3" bore. The shop only bored it out to suit the oversize pistons. The ports were not sanded. I have pulled the cylinder head off and there is light scuff marks on the cylinder walls, but you really can not see much with the head off. Ill post some pictures when I have a chance.
 
joereeves said:
I assume that the two affected cylinders were bored over-sized .030 (thirty thousands) and the remaining two were simply deglazed. Also assuming that you installed new piston rings on all pistons. You did have a service manual?

The carburetors..... It is mandatory that "all" carburetors be thoroughly cleaned and rebuilt when doing a powerhead overhaul as they are highly subject to jet fouling. Did you remove and thoroughly clean "all" of the high speed jets that are located in the bottom center of the carburetor float chambers? If not, do so.

Your first clue that something was drastically wrong was the engine not being able to exceed 1500 rpm... time to shut it down and begin trouble shooting.

However, you may be lucky... drop the lower unit as "Kim" suggests to determine if the seizing is with the powerhead or the lower unit. If with the powerhead, start with removing the cylinder heads to reinspect the pistons etc.

NOTE: If portions of a broken piston ring be becomes embedded in the cylinder head and cannot be removed, replace the cylinder head. To reuse a cylinder head in that condition will result in that portion of embedded steel to glow like a model airplane glow plug which in turn will result in pre-ignition, effectively causing the aluminum piston to melt down.
Click to expand...

This motor is a 3 cylinder motor. All 3 pistons were replaced with 0.03" oversize and I followed a service manual whilst doing this work. The carbs were thoroughly cleaned before starting the motor so I don't think this was due to a lack of fuel.
 
Did you do any work on the poppit valves / thermostat ??----The grommets on the valve seats might need to be replaced.
 
I would be looking at the simple stuff first as a probable cause.

Like, how much oil did you put in how much gas to get 25:1 ratio? Maybe you miscalculated.

That is, if you do truly have a seized engine due to lack of oil.

There is also the possibility that the machine shop did not set up the piston clearance properly, that you used Wiseco forged pistons (need more clearance), etc.
Automotive machine shops are notoriously bad at working with marine engines.
 
KSH said:
This motor is a 3 cylinder motor. All 3 pistons were replaced with 0.03" oversize and I followed a service manual whilst doing this work. The carbs were thoroughly cleaned before starting the motor so I don't think this was due to a lack of fuel.
Click to expand...

Sorry for the oversight (3 cylinder/4 cylinder)... I was aware that the engine was a three cylinder but was in the process of answering a couple other posts and apparently had an overlap.

I'm aware that you said the carburetors were cleaned... I was simply inquiring if the high speed jets may have been overlooked.
 
racerone said:
Did you do any work on the poppit valves / thermostat ??----The grommets on the valve seats might need to be replaced.
Click to expand...

These were removed and inspected. The seals still looked like they are in good order and the thermostats operation was checked. I'll be buying new ones along with the spring before restating it and the second rebuild.
 
joereeves said:
Sorry for the oversight (3 cylinder/4 cylinder)... I was aware that the engine was a three cylinder but was in the process of answering a couple other posts and apparently had an overlap.

I'm aware that you said the carburetors were cleaned... I was simply inquiring if the high speed jets may have been overlooked.
Click to expand...

No worries. The high speed jets were cleaned.
 
Oil was mixed at 800ml of oil to 20L petrol in a 45L container so it was mixed all together and is the correct ratio. The pistons were cast but that does not mean that the auto shop got it right. The only way I can measure that is with a dial bore gauge in the bore and a micrometer for the piston?
 
The centre bearings were not seated on the dowels properly which cause the crank to seize. There is some wear on my brand new pistons and bores. I will posted up photos of these to get some feedback on whether they still ok.
 
Pistons and rings should be fine to reinstall and continue with your ring seating run. Try and reinstall them as exactly as you can with rings in same orientation as they came out.


You will of course need new center bearings and your crankshaft's condition will be your main concern.


Would expect a machine shop should be able to confirm it's true and polish your journal's for you.
Have a happy Holiday,
Art
 
pilotart said:
Pistons and rings should be fine to reinstall and continue with your ring seating run. Try and reinstall them as exactly as you can with rings in same orientation as they came out.


You will of course need new center bearings and your crankshaft's condition will be your main concern.


Would expect a machine shop should be able to confirm it's true and polish your journal's for you.
Have a happy Holiday,
Art
Click to expand...


Took the powerhead to the machine shop today. They are going to check the crank and it is ok they will remove the dowel pins for me and lightly hone the light scuffing on the cylinders. Would the light scuffing on the cylinder walls result from the crank locking up or is this another issue?

Once I will get the ok I will order new center bearings and have another go. Fingers crossed it goes a little better for me this time.
 
Got my parts and have started to put the powerhead back together. I have a question though, with the cylinder head off and crankcase flange torqued up how freely should the flywheel spin? At the moment I can spin it with one hand but there seems to be a point which it gets a little stuck on and a bit more force is needed to get over this point.
 
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