top bearing on crankshaft is going bad

[bonitoman]

I was told my top bearing on my crankshaft of my v-4 johnson is going bad. Can i use the engine for a couple of days before i get it repaired.Thanks

 

[steelespike]

Re: top bearing on crankshaft is going bad

Hard to tell without seeing the problem.<br /> What did the mechanic say and why was it checked in the first place?<br /> If the bearing was to fail it could tear<br />things pretty bad.

 

[russthemuss]

Re: top bearing on crankshaft is going bad

My workers ran mine with a lower bearing gone,it stuffed the crank seal, ran lean on the bottom cylinder & stuffed the journal.Im still trying to find a second hand crank!!<br />Couple of days could cost you $$$

 

[Dhadley]

Re: top bearing on crankshaft is going bad

Why not just fix it???? Its very simple (you didnt tell us which V4 you have) in most cases and probably takes an hour or so. What makes you/him think its bad anyway?<br /><br />Good luck!

 

[bonitoman]

Re: top bearing on crankshaft is going bad

Thanks for the replies. The engine is a 1986 v-4 Johnson 110. Does the Powerhead have to be pulled and separated for the mechanic to change this? Can he just pull the flywheel ang get to this bearing. Thanks John

 

[bonitoman]

Re: top bearing on crankshaft is going bad

Dhadley , thanks for your information.I told the mechanic the engine runs great it is just at 5000 rpm you hear this rattling noise and he said it was my top bearing. MY question is , can he get to it from the top or pull the engine? My second question is there a test I can do to confirm what he says ? Thanks for the help

 

[Dhadley]

Re: top bearing on crankshaft is going bad

It's easy to change it on a V4 crossflow. Yes, as you said, he can just remove the flywheel, stator and timer base - pop out the 4 bolts and pull out the housing with the bearing in it.<br /><br />I hope thats the source of your noise.<br /><br />Good luck!

 

[realboats]

Re: top bearing on crankshaft is going bad

I have exactly the same motor and have done a lot of work to it, including replacement of the entire ignition system, pulling of the heads to inspect the cylinders, complete ring-out and cleaning or replacement of bad wire terminals. Finally got the engine so it runs really good and starts as soon as I press the starter button. But there's this klankity noise and I noticed a wobble in the flywheel. <br /><br />Pulled the flywheel (4th time!), stator and timer base. Unbolted and pulled the top crankcase head. The crank journal diameter was well within spec and smooth, although slightly darker in color than the rest of the crankshaft. I have to assume the roller bearing needs to be replaced.<br /><br />Question is, where can I get information on:<br />1) Finding a replacement bearing? Does OMC sell this or do I have to go aftermarket. I assume the old bearing can be removed from the crankcase head and replaced? Please don't tell me I have to replace the entire crankcase head...<br />2) Removal of the old bearing and installation of the new bearing? If heat is used, do I just use a propane tourch until the bearing assembly falls out?<br />3) Does failure of the top bearing mean the other crank bearings could need replacement also?<br /><br />What a heart breaker! Just when I thought the engine was ready to put back on the boat, and now this. :-(

 

[Walker]

Re: top bearing on crankshaft is going bad

realboats, that bearing is OMC proprietary and you can't get it anywhere else that I know of. Even worse is OMC doesn't sell the bearing. They will sell you the entire crankcase cap assembly with the bearing.

 

[realboats]

Re: top bearing on crankshaft is going bad

Thanks Walker. I've sent out a few emails inquiring about this. One web site claims they stock it. Iboats does not stock this part.<br /><br />If anyone out there can recommend a place to buy the top main bearing from, please send email to realboats@aol.com. The summer is slipping by fast!<br /><br />Johnson dealer wants over 300 bucks for the bearing/crankcase head!

 

[rayjay]

Re: top bearing on crankshaft is going bad

It's too bad they didn't just use a normal ball brg. Too cheap and easy I guess. It would have made the motor a little taller. On my 55hp the top brg is app $71 and you have to split the cases to change it. The lower brg is a ball brg in a removeable holder and you can buy that brg and seal separately.<br /><br />I just had a thought. I wonder if the brg you need is used in another motor without the holder ? It might be worth removing the holder, heating it up and removing the brg to get the numbers off it to compare. I am sure some of the omc specialists here could check to see if there is a cross reference once you had the brg in hand. You might need some vernier calipers to get some dimensions.

 

[Basscat 1]

Re: top bearing on crankshaft is going bad

If it is your bearing, after changing it, you need to find out why it went bad. If I am not mistaking there should be a small hole in the housing that oils that bearing. Make sure the hole is not clogged up. Follow it back into the intake to make sure its not clogged.<br />Without pulling it and doing a visiual inspection of the bearing, its hard to tell if its bad.

 

[realboats]

Re: top bearing on crankshaft is going bad

Thanks RayJay. I had wondered the same thing about the bearing being used on other motors. It's actually two rows of rollers stacked together into one cage to make a single bearing.<br />I believe they used only a single row prior to this which obviously wasn't adequate enough. It's really sleazy of Johnson to force their customers to buy the whole assembly.<br /><br />BassCat, I checked out the lube passage you mentioned. It starts at the crankcase head between the two o-rings, crosses over to the intake manifold, then goes down a groove on the intake manifold to places unknown to me. I tried fishing a soft wire through the passageway, but can't make that right angle turn on the intake manifold groove. Then I took a 10ml syringe about half full of two stroke oil, attached a plastic hose to it with a conical shapped rubber fitting that fit snugly into the lube hole, and injected the oil into the passageway. It all went through fine. <br /><br />That's not a foolproof test, but it at least tells me the lube passage goes somewhere and isn't blocked. Short of taking the carbs, intake manifold and all the attached junk off the powerhead, that's the best I can do for now. <br /><br />Dhadley or Joe Reeves? You guys around? Perhaps start a new post on this? Is it considered bad edequate to continue on with someone else's post even if on the same topic?<br /><br />Thanks for the inputs. I may have to break down and buy the whole assembly. Jeez, some household members are running short of patience with that darn motor if you get my drift. :-(

 

[Dhadley]

Re: top bearing on crankshaft is going bad

From the other thread --<br /><br />You can get an upper bearing from about any salvage yard or remanufacturer. Try Flagship (800-282-2840) or Superior Marine Salvage (800-338-9281).

 

[jy118lfd]

Re: top bearing on crankshaft is going bad

Check the timing could be detonation and that would be bad verrrry bad

 

[jy118lfd]

Re: top bearing on crankshaft is going bad

5000 is just about when the powerpacks get the extra 4 degrees of timing in

 

[realboats]

Re: top bearing on crankshaft is going bad

Thanks Dhandley, You are the man! <br /><br />Do you think it would be a good idea to pull the intake manifold and check the lube passages? Perhaps you have an easier/better way of checking for enough lube getting to the main bearing? I may as well do this right so I don't have to do it over.<br /><br />Thanks Jon. I didn't know that about the timing advance at 5000. Since the entire ignition system is brand off-the-shelf new, I'm hoping any possible problem like that has been resolved. I will check it very carefully though. Good thing to know, thanks for the advice!

 

[Dhadley]

Re: top bearing on crankshaft is going bad

I wouldnt worry too much about the oil passages right now. Since the bearing looks OK, chances are that it was getting oil. There will be some side to side play -- not much, but some. <br /><br />Are you sure the rattle youre hearing isnt just piston rattle? When you said you did a complete "ring-out" we assume you re-ringed the pistons. We further assumed that you honed the cylinders. If all that is true then its safe to assume that there was cylinder wear since the rings were worn. And if thats true then we can assume that after the honing the cylinders were really big. Given this it would not be unusual to have quite a bit of piston rattle.

 

[realboats]

Re: top bearing on crankshaft is going bad

Thanks Dhadley. I screwed up the terminology again. By "ring-out" I meant I rung out or checked all the wiring for continuity. Electronic techs use that term a lot. I took the wiring harness off, and checked each wire for continuity (actually found a few broken ones), then cleaned or replaced the lugs as needed. <br /><br />I'm sure the rattle was coming from the main bearing because first of all the flywheel was spinning with a wobble. Then, after shutting down engine, I grabbed and could move the flywheel fore and aft quite a bit and a bit side to side. I tried up and down play with a couple of small pry tools but felt no play. The real key something was wrong was that the flywheel actually scraped the paint off the side of the stator in places. <br /><br />If I had more time, I would pull off the intake manifold to check those passageways. The rollers on the main bearing have a brown color to them. They don't seem scored or out of shape in any way.<br /><br />I did pull the heads off early on in this project just to look at the cylinders and they were fine. No reason to change the rings or anything like that. Cylinder compression is within 5 pounds of each cylinder.<br /><br />If not for the main bearing, that engine was finally starting to run real sweet! I built a test water tank, and because the engine was running so smooth and so much quieter, the clanking of the main bearing became very noticeable. Please, please, please may this be the last major problem....

 

[realboats]

Re: top bearing on crankshaft is going bad

Just a follow-up. I ordered a new top main bearing from an outboard dealer on ebay. I also found a couple of web sites that offer it. It's definitely available aftermarker for about 100 bucks. Just do a google on "omc top main bearing". Here's the ebay add where I got mine. This guy really went out of his way to get me the bearing by Friday. http://cgi.ebay.com/ebaymotors/ws/e...tem=4532901920&category=50439&sspagename=WD1V <br /><br />I used a propane torch with a flame spreader and carefully heated up the crankcase head while gently tapping on the top of the bearing with a piece of wood. After about 3 or 4 minutes, the bearing just fell out. I quickly tried to insert the new bearing but the head had cooled just enough to contract so I had to apply heat again to get the new bearing in.<br /><br />I made sure there was plenty of 2 stroke oil on the bearing when installing. The orings and seal came from the dealer. The outside of the stator and inside of the timing base were both scuffed up quite badly from the bad bearing and resulting flywheel wobble. The old seal had a very interesting wear pattern; looked like a mouse had gotten at it. <br /><br />End result: Tighter than a bull's butt! Jeez, was I relieved! There is a very small amount of play for and aft, non side to side. The flywheel wobble is gone. Could this possibly be the last big problem for a while????<br /><br />Still a mystery what caused the bearing to fail, but I've been hearing that it's not that uncommon on that engine. Besides the problems mentioned above, someone else mentioned that gorilla gripped DIY'ers will use pry bars and hammers to get the flywheel off, distorting it and throwing it out of balance. The out of balance condition causes quite a strain on the bearing.<br /><br />Many thanks for the help and advice. I learned a lot from this and you folks are great!<br /><br />Anyone know how to test for an out of balance flywheel?