X flow bearing woes

[lorax]

I've been informed by a helpful soul on another forum (had trouble getting on this one for a while) that my Johnrude V4 should have almost no thrust movement (up/down) on the crankshaft.<br />He further informed me that if it does have play that the cause is the lower bearing and that the crank must be removed to replace it.<br /><br />Does this information sound about right?<br /><br />The engine runs good, is quiet and has good/consistant compression on all four. If I dismantle the power head to change the bearing what else should I do while I'm in there?<br /><br />Any thoughts? It's a '79 140HP on a '73 Glastron

 

[ob]

Re: X flow bearing woes

First off , if you feel that a bearing needs changing out you need to obtain thrust reading to determine whether you are in need.All motors must have SOME thrust movement or they would bind up to temp under load.Second, if motor is running well with no knocks and is operationally quiet, I would leave it be.

 

[Dhadley]

Re: X flow bearing woes

I did see someone told you to remove the crank but thats not true. If you even THINK the bottom bearing is bad -- change it. Simply pull the powerhead and remove the bottom housing. You will need a puller to get the bearing off. Repalce the bearing and away you go. Very simple.<br /><br />Yes, there is some play to the crank but to be honest I've never measured it. Again - if you think its bad -- change it!<br /><br />Good luck!

 

[lorax]

Re: X flow bearing woes

thank you both for your responses.<br /><br />I have yet to put a dial indicater on it but I can grab the fly wheel and move the crank up and down about .025 - .075 . I need to confirm that but I'll bet it's pretty close.<br /><br />Does that sound like a value that merits attention? I can't find a spec for it.<br /><br />Knowing that I can replace the bearing without disassmebling the powerhead is sure helpful.

 

[Dhadley]

Re: X flow bearing woes

The spec for the movement is the same as your level of peace of mind and confidence of not being stranded. There really isnt a written one. But there must be a reason you started your quest for this information. Noise? Vibration?<br /><br />Good luck!

 

[ob]

Re: X flow bearing woes

lorax, I don't know the specific tolerance for thrust on your motor .I've been a rotating equipment mechanic for most of my adult life and for what it's worth,I feel if thrust reading is in excess of .025 it may be cause for concern.If it is at or in excess of .050 it is most definately in need of attention.

 

[ob]

Re: X flow bearing woes

Hey lorax,Just put dial indicator on my 95 70 hp rude and total thrust was .006.Maybe this can help you with your judgement call.

 

[Dhadley]

Re: X flow bearing woes

The 3 cylinder looper doesnt have the retainer plate and screws like the crossflow. <br /><br />It may be nothing more than those 4 screws are loose. The bottom line is that its so simple to check its not worth not doing it. If those 4 screws come out it is possible to suck water in. For that reason alone I'd pop the p/h and look.<br /><br />Good luck!

 

[ob]

Re: X flow bearing woes

Dhadley, Thanks for that piece of info.

 

[lorax]

Re: X flow bearing woes

Thanks very much for the advise. <br /><br />I'm heading out with the dial indicator now. I really don't know what made me tug on that stupid flywheel in the first place.<br /><br />I bought the motor after my ol inline Merc scorched the number 3 cylinder(2nd time in 5 years). I was going to just fix the inline but when I spotted this Johnson for sale I thought I might be getting a slightly more reliable motor. That's pretty important when you're out on the Mississippi with you're 3 year old son <br /><br />Thanks again for the information

 

[lorax]

Re: X flow bearing woes

Well the magic number is .032"<br /><br />Guess I'll be taking apart the Johnrude.

 

[lorax]

Re: X flow bearing woes

I figure it's sometimes nice to hear the outcome when you've offered assistance on a forum so here goes:<br /><br />Pulled the power head, removed the lower bearing carrier, took off the "c" clip and gave the bearing a yank - hadn't even gotten out the gear puller yet. The bearing came right off <br /><br />heated up (just a little) the new bearing, tapped it right on with a socket of the right diameter. <br /><br />Although the old bearing really seems fine and the retainer bolts didn't seem loose, there is now, very little measurable thrust clearance.<br /><br />thanks for all the help.<br /><br />btw. what keeps the bearing retainer bolts from leaking air into the crankcase? The factory service manual makes no mention of sealing them.

 

[Walker]

Re: X flow bearing woes

Yes, you need to put sealer on the threads. I use locktite 518 on the threads and undside of the bolt heads.

 

[Dhadley]

Re: X flow bearing woes

The 4 bearing retainer bolts have an O ring type of seal on them. Look under the head of each bolt. They should be replaced and sealed with gasket sealer.<br /><br />Good luck!

 

[lorax]

Re: X flow bearing woes

You guys really bailed me out. Whoever worked on this motor last used ordinary, hardware store 1/4-28 screws for the bearing retainer.<br />I didn't know any better so I assumed that those screws where OK.<br />I'm suprised the motor ran as well as it did.<br /><br />Many, many thanks

 

[Dhadley]

Re: X flow bearing woes

The E/J number is 317763. Thats the ss screw and seal.<br /><br />If he did that I wonder what else he did? Like what did he seal the halves with? What did he do about rod bolts? Hummmm.....<br /><br />Good luck!

 

[lorax]

Re: X flow bearing woes

I'm trying not to think about what else he did <br /><br />thanks again