vintageglass
Petty Officer 3rd Class
- Joined
- Nov 22, 2010
- Messages
- 80
Hi, first post here, found this forum through a google search.
Back in March I bought a used 15' fiberglass boat, the motor was a good running 1982 60hp Johnson twin cylinder. I ran that motor about four times, then one day it was seized up. The tear down found a broken top piston rod.
It was propped to run 5400 RPM WOT, and was well treated as I knew the last owner for years.
In April I bought a used 1986 50hp twin for it, that lasted till August, when it too stopped running one day. Never a knock or any symptom, it just quit. Tear down of that motor showed a near identical failure.
Now, a few months later, I found a super clean 1990 40hp Evinrude, this one with oil injection and a remote tank. I bought that along with a boat which I resold. I swapped everything over as it was in that boat. Now two weeks later, that motor too lost the top piston rod, the damage is nearly identical to the first two motors. This motor was propped a bit taller, it only hit about 5100 WOT.
Is it me, or did these twin cylinder engines have a problem with breaking rods?
Each one failed the same way, the rod appears to have lost its end cap, the bolts are loose and undamaged, and the bearing is in 1,000 pieces. The cranks show no damage, but the block on the 40 and the first 60hp show damage. The part I don't get is that in all three cases, I was able to drive the boat to the trailer the last time out with no issues, then found it blown up the next time out. Never once did I hear a rod knock or rattle. The 60hp blew up the worst, as the rod end cap was found embedded in the piston top, the 50hp just came appart and looks almost as if I could replace the bearing and re-torque the rod and it would be fine. The 40hp blew a chunk out of the side of the block, I found one rod bolt in the pan, the other came out of the plug hole when I laid the motor down after removal.
I've owned outboards my whole life, just never small ones like these.
I've never had any other motors fail like this. Since there's no cylinder scoring or damage to the piston that wasn't caused by impacting loose parts against the cylinder head, I don't think it's a lack of oil, the 40hp was the only VRO motor, and since it was working fine on the other boat, (I drove it for a whole day before buying it), I'd have to say the VRO was OK. I don't see any signs that it starved for oil, and all three had new water pumps installed.
Back in March I bought a used 15' fiberglass boat, the motor was a good running 1982 60hp Johnson twin cylinder. I ran that motor about four times, then one day it was seized up. The tear down found a broken top piston rod.
It was propped to run 5400 RPM WOT, and was well treated as I knew the last owner for years.
In April I bought a used 1986 50hp twin for it, that lasted till August, when it too stopped running one day. Never a knock or any symptom, it just quit. Tear down of that motor showed a near identical failure.
Now, a few months later, I found a super clean 1990 40hp Evinrude, this one with oil injection and a remote tank. I bought that along with a boat which I resold. I swapped everything over as it was in that boat. Now two weeks later, that motor too lost the top piston rod, the damage is nearly identical to the first two motors. This motor was propped a bit taller, it only hit about 5100 WOT.
Is it me, or did these twin cylinder engines have a problem with breaking rods?
Each one failed the same way, the rod appears to have lost its end cap, the bolts are loose and undamaged, and the bearing is in 1,000 pieces. The cranks show no damage, but the block on the 40 and the first 60hp show damage. The part I don't get is that in all three cases, I was able to drive the boat to the trailer the last time out with no issues, then found it blown up the next time out. Never once did I hear a rod knock or rattle. The 60hp blew up the worst, as the rod end cap was found embedded in the piston top, the 50hp just came appart and looks almost as if I could replace the bearing and re-torque the rod and it would be fine. The 40hp blew a chunk out of the side of the block, I found one rod bolt in the pan, the other came out of the plug hole when I laid the motor down after removal.
I've owned outboards my whole life, just never small ones like these.
I've never had any other motors fail like this. Since there's no cylinder scoring or damage to the piston that wasn't caused by impacting loose parts against the cylinder head, I don't think it's a lack of oil, the 40hp was the only VRO motor, and since it was working fine on the other boat, (I drove it for a whole day before buying it), I'd have to say the VRO was OK. I don't see any signs that it starved for oil, and all three had new water pumps installed.