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1987 Evinrude 50 rod bearing

guido2

guido2

Regular Contributor
"This was a pristine well serv

"This was a pristine well serviced motor, had recent upgrades to VRO before signs of trouble. Customer hit underwater object at full speed end of last season with enough force to moderately damage prop, missing the skeg. Tilt/trim began leaking down from that point on. Customer brought me boat (primarily used for fishing small inland lakes here in MN). I repaired trim/tilt with used parts and rebuilt both cylinders with marginal improvement. Checked prop shaft and about .005 runout about halfway point. Replaced prop and checked torque on flywheel. Customer took out and on about 3rd tank of fuel, burned up #1 rod bearing. Bad knock the result. He wants insurance to cover the rebuild or replacement so I was instructed to partially tear down motor. Compression test #1 45psi #2 90 (my gauge runs little low). Pulled head, no wear or scoring or lack of oil. Lower rod beatiful. Without removing #2 piston I degreed crankshaft and found 2 to 3 degree off from TDC #2 to TDC mark on flywheel. After removing flywheel to check keyway for damage (all ok), then replaced flywheel, found still 2 to 3 degrees off. Showed all this in front of insurance adjuster and he won't buy that the crankshaft is twisted or bent. Does anyone think we have a case here? Motor is not covered but he will repair prop and trim/tilt unit. Would 2 or 3 degrees indicate enough trama to crank/rods to cause this failure? Rod bolts on #1 were finger tight. Thanx.....we need a real pro on this one. Tim"
 
No way You may manage to '

No way You may manage to 'twist' the crank shaft from that kind of 'minor' impact.
Most likely a bearing failure caused by lack of fuel/oil.
Why the recent 'upgrade' to VRO?
Most possibly an old 'damage' that finally surfaced.
 
"Hi, thanx. I build dirt track

"Hi, thanx. I build dirt track race car engines and they can bend a crankshaft or damage a rod from sudden engine speed or loading changes. We run upwards of 600 hp from 400 chevs and use steel crankshafts......they twist and bend. My dad had a brand new 402 Merc tiller and hit a rock at full speed on his second outing. The motor survived that 3 day trip. The next time he used it a few weeks later, the crankshaft broke in two. Merc covered it on warrantee and the repairman said "what the hell did you hit". I still have the motor....that was 1976 and the replacement powerhead is still going strong. Thanx, Tim"
 
"Mr Ringvold, sorry...forgot t

"Mr Ringvold, sorry...forgot to tell you that that the VRO was replaced because it was "over" injecting. Thanx, Tim"
 
"'Moderate damage of prop&

"'Moderate damage of prop' (I take it was an alu prop)will never result in a twisted crank shaft!
I in fact doubt that even a blade-less SST will do that on the 40/40 Evinrude Johnson. You will strip the gears and twist off the drive shaft long before that! Have a look at the upper splines on the driveshaft. Are they still 'straight'?
A VRO can not 'over inject' oil. What may happen is that it does not deliver enough fuel compared to the amount of oil injected. That might indicate that the engine has been running lean for some time with crank case combustion which may have shocked loose the rod screws, or the screws have not been tightened to correct torque at assembly. Did you use a piston stop or dial gauge to establish the TDC? How did you manage to do it with a failed bearing?"
 
"Hello sir, Tim again. Used a

"Hello sir, Tim again. Used a dial indicator on #2 cyl clamped to a head bolt. Reconfigured a couple different times with same results. The #2 cyl had perfect bearing and wrist pin so no slop was involved other than the normal "over the top" 2 degrees. I checked another 1994 40hp that I have here that the VRO starved out of oil. This other motor is scored cylinders with .003 average wear in top half of both cylinders. The upper rod bearing is burned moderately but not with needle bearings melted to the retainer like the 50hp. The 50hp has about .001 max wear in each cylinder and a lite hone would clean it up nicely. I checked the 40hp with a dial indicator the same way as I checked the 50hp and the TBC (top bottom center) cyl #2 is right on to TDC mark on flywheel. Note: Never pulled powerhead or lower unit yet on 50hp so can't examine driveshaft splines. Just looking for clues as to the reason for failure. Yes the prop is aluminum and the customer said it was too deep to be a rock and suspects a partially submerged log here in the St. Louis R. which flows into L. Superior here in Duluth. My dad hit a similar object while motoring with a 15hp Johnson and it broke the motor off the transom, it ended up in his lap. For a couple years in the 80,s the 15's had piss poor casting engineering that attaches the motor to the main transom bracket. By late 80's they had refined that part to correct the defect. He fished with 2 15,s and ran both when running to different fishing spots. Portaging into remote areas of NW Ontario taught him to keep 2 motors around 'cause you'll rarely find any outside help. I never saw the prop after the original incident on this 50 because the customer had it patched up by his father-in-law to keep as a spare in an emergency. However you can see where the blades were bent and he made a cut to weld on new pieces, about 1/3 of one blade was missing with less damage to the other 2. The skeg is slightly bent to one side with no evidence of abrasion from a rock. Thanx, Tim"
 
"Hi, Tim here. Is there a way

"Hi, Tim here. Is there a way I could post some cyl and piston photos on this site? Thanx"
 
"On a johnson SST60 race engin

"On a johnson SST60 race engine that i have rebuilt i checked the crank timing with a degree wheel etc and found a couple of degrees difference my opion is the impact didnt twist the crank,,,like mort said "You will strip the gears and twist off the drive shaft long before that! Have a look at the upper splines on the driveshaft. Are they still 'straight'?""
 
"I hate to close out this subj

"I hate to close out this subject without getting some imput from Mr. Reeves. Thanx, Tim"
 
"Due to age, eyesight problem

"Due to age, eyesight problem etc, I avoid problems that are put into one long drawn out paragraph. In trying to read those long single paragraphs, everything has a tendency to run together within a short length of time.

Short paragraphs such as you see here make for easy reading and eliminates confusion due to having lines criss cross, flow together, etc.

However, if you're asking me if the crankshaft is twisted.... it is not. As mentioned above, the driveshaft would shear before that scenario could take place.

Was that the only question?"
 
"Thanx, Mr Reeves. Could the l

"Thanx, Mr Reeves. Could the log strike have caused the connecting rod bearing failure? Engine is pristine, no cyl wear or scoring."
 
"Connecting rod failure is usu

"Connecting rod failure is usually due to a fouled carburetor that would result in a lean mixture (improper lubrication).

Hitting a object with the propeller at full speed would normally result in a bent propshaft but I've never heard of a lower unit strike affecting the powerhead in any manner.

The PTT leaking down after being hit would indicate that the lower unit was hit hard enough to cause the PTT to release, having the engine forced up and out of the water momentarily. This could result in having the "impact valve" jammed slightly open BUT of course, the many other valves could be affected also.

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"Thank you Joe, we will try to

"Thank you Joe, we will try to repair the 50 hp if the customer can recover some funds from his insurance company.
We won't have to bore it, but a kit with standard pistons would be the best value.
Do you have a used crankshaft at your store?"
 
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