Bearings…help!

[anthony_marquart]

Tim is right.. we can all guess at it.. I would say there is a systemic error in the way you are running them though..

As Terry said,.. it would have to know the pipe and length, The fuel brand and percentage, prop and details.

too much prop, too short of pipe, combined with too much cooling and lean needle,.. will tear up any motor.

 

[Robert Elder]

Hi Robert

We would love to have you come out to Beamsville and go over your boat with you, we have plenty of Nitro and Nova experience in our club and would like to help.

Send me a PM if you like and we can set up a date to meet at the pond.

Tim

Thanks for the offer, Tim. I have recently started a business so my time is not my own these days. Including the Sunday that this happened, I have been out to our local club pond a total of two times so far this year :-(

 

[Robert Elder]

I doubt flushing with WD40 and using ATF as an after run would have anything to do with hurting a motor, quite the opposite.

You didn't answer my question, I'll ask again. So both times it "seized up" was because the rear bearing failed?

Please elaborate:

"I have had a hell of a time getting it to run hot enough - even with the water turned off. In fact, I have never even turned the water on."

Over propped, over cooled = over leaned

I think my initial reply is valid.

Thanks for the suggestions. I don't know if the first time it was a rear bearing. I never pulled the crankshaft out to check - just replaced the motor but I will dig out the old motor and do it in the coming days.

Prop was worked for that boat (H7 that came off Mike Hallam's). I suppose it could have been too much for the boat but I wouldn't think it wouldn't be that much. For the last run, I had actually propped down. Joe had commented the last time I was out that it sounded 'like it was pushing a load of stones uphill" but it had run pretty well. Upper 50's, I would say and reliably, (that was the first run for the year).

As for over cooling, I never had any water to the head. Only cooling was exposure to the air. I could add a cowl to restrict that I suppose.

As for over lean, it could be. I have been trying my best not to be too lean but at richer settings it would run very poorly and spit fuel out the pipe.

btw pipe is a NR quiet pipe and from the plug to the weld, (along the centreline of the tube) was about 7 1/2". Fuel was RedMax or Wildcat that i got from Mike Hallam.

 

[Terry Keeley]

I doubt flushing with WD40 and using ATF as an after run would have anything to do with hurting a motor, quite the opposite.

You didn't answer my question, I'll ask again. So both times it "seized up" was because the rear bearing failed?

Please elaborate:

"I have had a hell of a time getting it to run hot enough - even with the water turned off. In fact, I have never even turned the water on."

Over propped, over cooled = over leaned

I think my initial reply is valid.

Thanks for the suggestions. I don't know if the first time it was a rear bearing. I never pulled the crankshaft out to check - just replaced the motor but I will dig out the old motor and do it in the coming days.

Prop was worked for that boat (H7 that came off Mike Hallam's). I suppose it could have been too much for the boat but I wouldn't think it wouldn't be that much. For the last run, I had actually propped down. Joe had commented the last time I was out that it sounded 'like it was pushing a load of stones uphill" but it had run pretty well. Upper 50's, I would say and reliably, (that was the first run for the year).

As for over cooling, I never had any water to the head. Only cooling was exposure to the air. I could add a cowl to restrict that I suppose.

As for over lean, it could be. I have been trying my best not to be too lean but at richer settings it would run very poorly and spit fuel out the pipe.

btw pipe is a NR quiet pipe and from the plug to the weld, (along the centreline of the tube) was about 7 1/2". Fuel was RedMax or Wildcat that i got from Mike Hallam.

Now I think we're getting somewhere.

Really sounds to me like you're just "over center" and had to lean it down to go. I don't run 20 hydro's but am pretty sure an H7 is a lot of prop. I do know that 7 1/2" is very short, 8 - 8 1/4" would be a better starting point. Get a stock X448 or 1450 or pull the strut up to lessen the load.

Haven't been a fan of completely removing the water, even for break in. Find it better to restrict it some way. Ask Joe for an old needle valve and put it in after the rudder, that or solder the fitting on the rudder shut and drill it out with a #60 (0.040") or smaller drill.

Any idea what the head clearance is? 21's are fussy on that...

 

[D-7]

Robert you are not alone !

many good drivers in Europe have the same problems, the big ballbearings have service life of 30-45 minutes / ceramic bearings are slightly better.

 

[dwilfong]

get a bearing with the right radial clearance and this bearing problem will go away.

 

[Robert Elder]

I doubt flushing with WD40 and using ATF as an after run would have anything to do with hurting a motor, quite the opposite.

You didn't answer my question, I'll ask again. So both times it "seized up" was because the rear bearing failed?

Please elaborate:

"I have had a hell of a time getting it to run hot enough - even with the water turned off. In fact, I have never even turned the water on."

Over propped, over cooled = over leaned

I think my initial reply is valid.

Thanks for the suggestions. I don't know if the first time it was a rear bearing. I never pulled the crankshaft out to check - just replaced the motor but I will dig out the old motor and do it in the coming days.

Prop was worked for that boat (H7 that came off Mike Hallam's). I suppose it could have been too much for the boat but I wouldn't think it wouldn't be that much. For the last run, I had actually propped down. Joe had commented the last time I was out that it sounded 'like it was pushing a load of stones uphill" but it had run pretty well. Upper 50's, I would say and reliably, (that was the first run for the year).

As for over cooling, I never had any water to the head. Only cooling was exposure to the air. I could add a cowl to restrict that I suppose.

As for over lean, it could be. I have been trying my best not to be too lean but at richer settings it would run very poorly and spit fuel out the pipe.

btw pipe is a NR quiet pipe and from the plug to the weld, (along the centreline of the tube) was about 7 1/2". Fuel was RedMax or Wildcat that i got from Mike Hallam.

Now I think we're getting somewhere.

Really sounds to me like you're just "over center" and had to lean it down to go. I don't run 20 hydro's but am pretty sure an H7 is a lot of prop. I do know that 7 1/2" is very short, 8 - 8 1/4" would be a better starting point. Get a stock X448 or 1450 or pull the strut up to lessen the load.

Haven't been a fan of completely removing the water, even for break in. Find it better to restrict it some way. Ask Joe for an old needle valve and put it in after the rudder, that or solder the fitting on the rudder shut and drill it out with a #60 (0.040") or smaller drill.

Any idea what the head clearance is? 21's are fussy on that...

I have a valve on the water line. I just didn't open it because we never got to the point where it was too hot.

I can certainly prop down and pull the pipe out to 8 1/4", (or at least as much as the header will allow). That would be great if those were the issues - easy to fix

The strut is at the bottom of the ski, right where the instructions say to put it.

As for head clearance I remember pulling out one of the shims but leaving the other two. Glenn told me which to remove.

 

[Robert Elder]

get a bearing with the right radial clearance and this bearing problem will go away.

Glenn has offered to do the rebuild, (which I think is great) so I think I will send him the pieces and let him work his magic.

 

[David Murany]

Running the engine lean sounds like the culprit to me. You think the elements just blow out the pipe but they end up in the bearing a lot of the time. We run every weekend and only use WD40 for after run and don't have these failures. The H7 with a 7.5 inch pipe length is short. Go to 8 inches and restrict the water. A 21 engine should operate at 200 degrees Fahrenheit. Hope you get it figured out.

Dave

 

[darin christensen]

To get that stuck bearing race off the crank you need to concentrate heat only on the bearing race. When you heated the crank in the oven you expanded the crank along with the bearing race there`s no way in hell it will come off doing it that way. You can also shoot some penetrating oil on the bearing race and soak it before you use heat. When your ready heat up the bearing race good and hot ( it doesn`t need to be glowing red ) then hold the race lightly with a pair of pliers and with a small rubber mallet tap the crank out. Good luck

 

[shoboat]

Robert,

No water was your problem.

Too Hot and Too Lean !!!

Richen your needle on your new engine and add some water .040" and you will

have fun again. Most 21 inboard engines run way too hot for no water at all.

Were you running the stock carb? .350" bore?

Have Fun Richen Up And Use A Little Water,

Mark Sholund

 

[steve wood]

just randomly pulling head shims out of a nova can be a big problem. I have seen several motors that people have done this too,without checking things over carefully. just had one like this a couple weeks ago.some one had taken out enough head shims so that the head button was resting on the casting at the top of the case,and was not even touching the top of the liner. no head to liner seal,liner allowed to "float" in the case,piston contacting the head button,etc. engine was junk. I mill the top of the case of every nova I work on,so this can never happen.another way is to turn some material from the bottom of the head button,but if the button is changed out and this isn't taken care of it can happen again. this is nothing new. they have been like this since they went to the water jacket had the 2 orings,at least 15 years. if you can't see a gap between the bottom of the button and the top of the case, fix it ,if it's not too late

 

[Robert Elder]

We got the bearings out of the 1st engine and it was the rear bearing that failed that time too.

 

[Tom Foley]

just randomly pulling head shims out of a nova can be a big problem. I have seen several motors that people have done this too,without checking things over carefully. just had one like this a couple weeks ago.some one had taken out enough head shims so that the head button was resting on the casting at the top of the case,and was not even touching the top of the liner. no head to liner seal,liner allowed to "float" in the case,piston contacting the head button,etc. engine was junk. I mill the top of the case of every nova I work on,so this can never happen.another way is to turn some material from the bottom of the head button,but if the button is changed out and this isn't taken care of it can happen again. this is nothing new. they have been like this since they went to the water jacket had the 2 orings,at least 15 years. if you can't see a gap between the bottom of the button and the top of the case, fix it ,if it's not too late

Great post Steve !

 

[Terry Keeley]

get a bearing with the right radial clearance and this bearing problem will go away.

Glenn has offered to do the rebuild, (which I think is great) so I think I will send him the pieces and let him work his magic.

We are very lucky to have such a great person to distribute NR over here, good luck!