motor lock-up @4000 rpm; how much damage?

[GlasV162]

Hi,
1990 Evinrude 90 hp vro

Just spent about 2 hrs. on the lake w/ my mechanic diagnosing a problem at high rpm; turned out it was a piece of dirt in one of the carb jets. Got that fixed then went back out on the lake; motor ran great, but then locked up while running at about 4000 rpm; called my mech and he told me to put oil in the straight gas and start it up again and make sure it smoked. It started right up again like nothing happened, and it smoked so I knew it was getting oil. He met me at the lake and we went for another lake test. It runs great and sounds great, so my question is this: is there any idea how much damage was done? After this scare, needless to say I'm going premix. He said he's seen motors lock up like mine did 4 or 5 times and still run, and that if serious damage was done, I'd know it by now; maybe scored the cylinder walls a bit, but running it now will "smooth them out again." Any advice?
Thanks

 

[F_R]

Re: motor lock-up @4000 rpm; how much damage?

If it was ran without oil to the point of lock-up, I don't see how it could not have been damaged some. I agree that you would know it by now. Maybe this is your lucky day. Then again....

 

[iwombat]

Re: motor lock-up @4000 rpm; how much damage?

The only way I know of to "smooth out" a scored hole is to rebore the next size (or two) up. Running the pistons up and down certainly won't do it.

I'm surprised your oil horn didn't go off.

Edit: Maybe you can be a little more specific about the history of this motor and what your mechanic has done. It'd be helpful in advising you on a course of action.

 

[GlasV162]

Re: motor lock-up @4000 rpm; how much damage?

He rebuilt it over the winter--new pistons, rings, bearings and rebuilt the carburetors. It's been back to his shop 4 times this summer since the rebuild with no top-end power. Turns out it was a piece of dirt in one of the jets. After getting that taken care of I went back out onto the lake; that's when she locked-up. It was then that I called him back and he came out to the lake to run it some more with pre-mix and it still runs great. But after it locking up, I have to admit I don't have a lot of confidence in the motor, even though it still runs as strong as ever. No alarm went off. Does the vro have any other alarm other than the one that monitors the oil level in the tank? It would seem to me that in today's modern world that these pumps would have a sensor that would either sound an alarm or stop the motor if oil stops flowing.

 

[Dennisanoka]

Re: motor lock-up @4000 rpm; how much damage?

Yes the VRO itself has a no oil alarm. You can read all about it here. http://continuouswave.com/whaler/reference/VRO.html And there is the one in the oil tank also explained in the same article. I know how much you have struggled with this engine and the mechanic. Was the engine yours to begin with and he re-built it? I'm sorry I don't remember.
At this stage if it were me and you think he might stand behind his work I would want to look at the cylinder walls. Whether he'll fix them or not. Each head gasket is about $8 so all you are out is $16 if they are still smooth as a baby's, you know what. If they are scored and as he found ,caused by dirt in carbs that he re-built, well I think there's responsibilty for him to make them right if possible. I know your frustration level is high but just do your best to stay cool because right now he is still your best shot to get it fixed without starting all over somewhere else at your $.
Maybe you'll get other advice here, but I'd want to know with my own two eyes that at least the cylinder walls are ok.
How did he get the dirt out of the carbs? Did he pull them off when you were there?

 

[iwombat]

Re: motor lock-up @4000 rpm; how much damage?

Maybe some of the other pro mechanics can chime in here, but I'd think verifying all the alarms work properly (this includes the VRO alarm) after a powerhead reinstall should be standard operating procedure. Verifying the VRO works properly should be right up there too.

Did you get a break-in procedure? It should of included a 50:1 premix on top of what the VRO is supplying for a fixed number of hours anyway. If not, did he do the break-in at the shop?

 

[GlasV162]

Re: motor lock-up @4000 rpm; how much damage?

I don't know if they checked the alarm operation or not, but I'm going to ask him. As for the dirt in the carburetor, it would seem to me that even a newly-rebuilt carb could still get plugged if a piece of dirt got sucked out of the gas tank. No? I fully expect him to stand behind his work, but I also want to be fair and understand that things do happen that are out of his control. Now that I know there is a no-oil flow alarm, I'm even more concerned because after the lock-up, I asked the mechanic if the motor has such an alarm, and his response to me was "F-ck no. Only an alarm for low oil level in the tank."

He told me to run it the way it is; what I need to find out from the shop owner is if he will still warranty the powerhead knowing that it has already locked up. Either way, I'm disconnecting the vro; I'm afraid of it now. Should I run the normal 50:1 ratio, or should I run with extra oil? And yes, the motor was mine; owned it for almost 6 years. I'm told the way to disconnect the vro is to unplug the wire harness and plug the oil line going into the pump. Is that correct?

 

[iwombat]

Re: motor lock-up @4000 rpm; how much damage?

It's a newly rebuilt motor, that had issues the minute it left the shop. The alarms and VRO operation weren't tested properly before it left. You bet the shop owner should honor the warranty. All you've done is operate it normally - for 4 hours! You should run that at 24:1 for the first 10 hours or so. Better yet, tell the shop owner you weren't given break-in procedures and could he please provide some.

Yes, it's easy to forgive the dirt in the carb to a degree. It should have been run in a test tank for a shake-out period. That should have surfaced the dirty carb before you ever got it. However, even then it's possible.

 

[Chris1956]

Re: motor lock-up @4000 rpm; how much damage?

Usually the rings require the most lubrication, and therefore suffer the most when lubrication is inadequate. The bearings seem to suffer little or no damage, in comparison.

You need to take a copression check on the motor. My experience is that the motor will lose low-end power after it seizes. This should manifest itself in low compression. I have had some 2cycle motors that ran OK after a seize, but it is not common. My friend ran his inline four Merc without oil twice, before it refused to start, due to low compression. The rings had welded themselves to the piston grooves. I honed the cylinders, drove the rings out of the grooves with a punch, installed new standard rings and reassembled the motor. it ran OK, but was quite down on low end power. I do not recommend this course of action BTW, but it was appropriate for me at the time.

 

[mikesea]

Re: motor lock-up @4000 rpm; how much damage?

Insist the guy do a compression test NOW,then remove the heads for inspection,on a new rebuilt,you comp.readings should all be the same,stand next to him as he does the test.I have worked in 2 p/h rebuild shops,and they actually had 2 different procedures ofrebuilding that I wont get into,BUT,both made absolutly sure the engines were run prior to delivery,usually (due to location)we would idle the boat around,checking all cable adjustments,leaks etc,then let idle at the dock for a couple hrs.But when delivered,all possibility of dirty carbs wee eliminated,one shop gave a better warranty if the vro was DISCONNECTED and premix used.The other we put on a new VRO regardless.Owners policies

 

[GlasV162]

Re: motor lock-up @4000 rpm; how much damage?

Thanks.......I may just do a compression check myself; a couple of the local auto parts stores loan the testers out; any trick to doing a compression test myself? Cold test? Warm test? Thanks.

 

[iwombat]

Re: motor lock-up @4000 rpm; how much damage?

You need to stand up to your shop and demand some service. Doing it yourself just opens up more reasons for the shop to not stand behind their warranty. DON'T TOUCH THIS MOTOR ON YOUR OWN. You paid for service, make them give you some.

 

[mikesea]

Re: motor lock-up @4000 rpm; how much damage?

I understand iwombats point,however,doing a comp.test on your own should not void any warranty,and with the poor performance you have had you need to be on guard. I like to have a heads up when I can. remove all plugs and test each cylinder by cranking the eng.for about 10 seconds ,or until the gauge stops,write thereadings down.whether you want to tell the guy you did it on your own is up to you,but if any readings show low,call him and insist he cme out and do a comp test because your apprehensive about using the boat now.then when he does the test compare the readings,its possible to have a differance in readings depending on the tester,but it shouldnt be much,if the readings are low have HIM remove the head in your presance and see if cyl walls in each cyl look the same,top of pistons ,be SURE to put the spark plugs back in the cyl they came out of,look for signs of wear on the plugs,you might see aluminium deposits,perhaps it may look beat up,keep us posted

 

[iwombat]

Re: motor lock-up @4000 rpm; how much damage?

Personally, I wouldn't put a wrench on it until the shop delivered something that worked. By doing so, you're implying accepted ownership and delivery.

Just my $.02

 

[GlasV162]

Re: motor lock-up @4000 rpm; how much damage?

Well the plot thickens. Stopped by the shop on my way home to pick up some oil for premixing. The owner and mech. asked how my motor is running and I told them tonight will be the first time out since the day it locked up. I asked about doing a compression check and he said he would do it, so will bring it in tomorrow a.m.
Now, out on the lake tonight, it ran great for about 15 min. and is now running bad at top end again, just like when the dirt was in the carb jet. I pulled the plugs and they're pretty gunky; The gas I'm on is at least double oil. I put in a new set of plugs and will try it in the lake again tomorrow a.m. before going to the shop; if it still runs bad I'm going to have them check the carbs again. Any other suggestions would be much appreciated. Thanks.

 

[beau123]

Re: motor lock-up @4000 rpm; how much damage?

It's probably not gonna run great due to the double oil. But I would definately take it back to the shop and have them do a compression test. Also I would ask if they would pull the heads so the cyl. walls could be inspected. They should stand behind their work and honor the warranty.

 

[GlasV162]

Re: motor lock-up @4000 rpm; how much damage?

Yes, I agree. I have my doubts though--he's put in a lot of extra time on this one and is probably losing money every time I come back to the shop with it. Also, today at the shop I told him I want to bypass the vro and go premix, as I don't want to risk another lockup. He told me all I have to do is run the vro tank dry and disconnect the wires for the low oil level alarm. I'm confused because I've read in here that the oil line going to the vro pump should be plugged to keep it from sucking air into the fuel system. Any insight on this would help as well. Thanks.

 

[GlasV162]

Re: motor lock-up @4000 rpm; how much damage?

Still more...........
When I was at the shop today I asked him if the vro alarm system was checked after putting the motor back together, and he said "no." I guess that explains why the alarm never sounded prior to my motor locking up.

 

[beau123]

Re: motor lock-up @4000 rpm; how much damage?

I would think you should plug the line. Someone a little more experienced will let you know. But what startles me is that he didn't check the alarm. Seems that, that would be on the to-do list. Let us know how everything turns out.

 

[GlasV162]

Re: motor lock-up @4000 rpm; how much damage?

Well it's still running bad at top-end. Tried it early this a.m. with new plugs and still the same problem. Stopped by the shop, mech. did a comp. check and all 4 cylinders were 150 lbs. each. However, on the bottom starboard spark plug there were some small metal filings. My mechanic said those filings would cause a plug to short out and not fire and consequently, foul up. He put a new set of plugs in, he sent me back to the lake to test it this morning and it still runs bad at top end, like it's not getting fuel. Back to the shop I went (trip # 6 since the rebuild). More filings in the bottom starboard cylinder. He said the motor needs to run and "clean itself out." He's going to check the carbs again too to see if it picked up another piece of dirt in one of the jets, and install a water/fuel separator/filter.
I'm concerned about his remark about it needs to "clean itself out." This just doesn't sound right to me. I'm not a mechanic, but I'm smart enough to know that a motor isn't going to fix itself. Any suggestions? Thanks.