Hot Bravo XR
 

Is there any specific that could cause an XR to run hot? Not looking for the run it too long, too hard answer. But for something in the actual set up of the drive when it is assembled.

Yes if the shift linkage goes too deep, it will allow the cam to rub on the brass ring. That will cause excessive heat. Or if the gear stack is too tight, same thing.
Besides the normal, bad bearing, no lube, etc. But that would indicate a broken drive.

Hope this helps.
Dick

Thanks! Anything else to look for? The gear lube, Amsoil, has a burnt smell after 20 or so hours. Drive seems to work fine just concerned at this point, lube in the other drive is fine. Plan to change lube on both today and check magnets for any sign of metal.

Gadgets would know more than me about the drive, but that oil, shouldn't have any burnt smell at 20 hours, so there might be something else going on. Not trying to start any holy wars here, but that AMSOIL gear lube is the best on the market.

Tell the wife to quit sitting on it....

It will not last for long ....the advise is split it appart and re-check tolerance ...i know they happen to me

Is the drive new, or just been reassembled? I take it is freshly assembled.
If new gears are installed and the inner bearings are not washed and lubed properly, they can not spin on the tower and burn that up. But usually within 3-5hrs it will seize up and break.
If anything is too tight, it will cause heat. Either tear it back down or pull the back cap and look for signs of heat. The shift fork may be rubbing and it will be blue and worn deep. The shift cam at it's thickest point will have wear marks into the metal if they are rubbing hard on the brass rings.
Stuck or broken bearings will cause heat.
An inspection would be the best thing. You may be able to avoid real damage.
And no matter what oil you run.. it shouldnt smell burnt. There is something not right in there. :(

Dick

Too much fuzzie chit on the lower magnet so I had it gone thru, freshened would be the term I guess. New bearings , thrust bearings, upper drive shaft, top cap and bearing, seals etc. Gears and cone clutch were fine. Set up, pressure tested and reinstalled 20 +/- hrs ago. Noticed a little too much expansion in the bottle after a hard run and checked the lube, burnt smell, not good!

Don't think in any way that the Amsoil has anything to do with this, it's just running too hot, and looking for possble reasons. Dumped the lube this afternoon and it's toasted, also have the chunks on the magnets again, more so on the lower one than the upper.

Thanks for the info, keep it comming.

high heat
 

Sounds like a tolerance problem somewhere...

Too tight pinion bearings are one of the things that I see most often and they generate TONS of heat.
Amsoil is good stuff but we have gone back to the good ole Merc HP oil for its "solids/suspension" package. Our experience is that the synthetics will drop gear oil temps but your metal to metal wear under high loads (Momentary high PSI) will increase. We also tested Red-Line that seemed a little better.

A Billet Water cooled topcap will drop 50+ degrees from gear oil temperatures on hard runs...
www.billetmarine.com

It would be well worth a tear down and inspection by a local shop...

Good luck, Curtis @ Billet Marine

Your statement doesn't make too much sense when it comes to synthetics. You say they'll drop temperature, however metal contact will increase? With more metal contact, more heat would be created. I've never seen, in my 20 years of business, a petroleum product out perform a high quality synthetic. If I were you, I'd do my testing again.

Well the drive was toasted. Torn down now and all the new parts from the last deal are shot, along with the gears now being shot. Took out the brand new upper drive shaft again, as well as the brand new top cap and bearing that was replaced in the last go-round. Foreward gear and pinion gear have chunks out of them and metal is thruout the entire drive. Just love this chit!

Heat problem in my mind, set up too tight, nothing to do with the gear lube.

Sorry to here about that Peter. Hope you get it worked out.

Hate to hear that!! Sorry for the mess. It sounds like it wasnt put together properly..
Let me ask, was the race on the tower in the case burned up? Like the bearing in the gear was not rotating?

Hope you can work it out.. :(

Dick

What was torn up was the pinion gear and foreward gear, the face of the teeth are pitted/chunks of metal missing on the face of every tooth of both gears, the reverse gear is fine, and the cone clutch looks perfect. On the upper driveshaft there is some metal torn out on the surface that contacts the bearing in the tower, this is about a third of the way around the surface, rest of the way around it is fine. The top cap surface where the shim/race rides is also torn up and has some metal imbeded in the machined surface. The inside surface of both drive gears where the bearing rides are darkened, I assume heat discoloration. The bearings in general look ok to the eye, I have nixed the idea of using any of them and have all new being installed.

Questions here,
Is the set up of the new swept back style XR drive different in spec than the older style XR's ?
What should I stress they be attentive to when rebuilding this drive this time around?
Am I close to right in thinking it was shimed to tight, the gear lube was very burned and stunk like chit with about 20 hours of use?

Thanks VV. Well if it can't get straightened out they make new ones every day, by the time I'm done this time around I could have just bought a new upper to start with :eek:.

The setup on the newer drives did change a while back. I know the hump backs use this, but it was implemented on the older style XR a year or so before the humps came out.
But it is in the shimming of the depth of the pinion gear itself. They use a wire shim to set the pinion depth.
If the bearings in new gears are not washed and properly lubricated they can slide on the tower races and stick and burn up. But you would see the bearings worn flat, not just heat bluing.
The pinion and driven gear, both being pitted would indicate to me a tight lash problem. If they are too tight, they can self destruct in a short time, with the results you are describing.
Upper clutch shaft with wear on the inner tower bearing surface is getting more common (can you say China?) If it doesnt destroy the inner tower bearing, then it might not be the cause of the whole failure, but would have been a disaster when that bearing failed. I have seen the upper shaft broken and the inner tower bearings destoryed. Which came first? (Chicken or the Egg? thing)
The proper setup and lash of the gears is important. There are several ways to accomplish this, but in the end the if it is wrong, it wont last long.
A simple check for a novice would be to pull the back cap and wiggle the driven gear with the pinion stationary and see if there is some play. There should be some play in it.. It is measured with the pinion gear during setup, so numbers are not important just some play is the goal.

Hope this helps.
If you want to discuss it give me a call..
616-403-1006

Thank you! I am going up this afternoon to check on the progress. They can't finish it without the cap which I have. So I will talk with the tech, he's been at this a long time and did both drives on my last Fountain with no issues. I'm just thinking second time here might warrant a real close look at the set up to make sure it stays together this time. Appreciate the tips.

Looks like you cought it early and salvaged alot of the drive. Keep us posted....

Well it's all good now. Just got home from the marina and it's back on and ready to run tomorow. Everything was double checked, pinion set and shimed, back lash on the gears set, pressure tested and good to go. Shims are a little different than last time around, could be new gear set or whatever, but set up seems good now. I drained the other one this afternoon and the lube was fine, no chit on the magnets either, so I guess I'm back in business.

Thanks to Mr. Gadgets for the tips! Your advice allowed me to have a conversation with the tech without any feathers being ruffled. I've known this guy for many years and really wanted to avoid that. Thanks again!

But one more question for you .......... Should this thing be "broken in", run easy for a few hours or something?

I'm gona guess...3hr's various rpms not to exceed 4000 rpms then mash the sh!t out of it....

I recommend the first 5 hrs run easy.. Let it loosen up and let the gears break in. Then drain the metal out and keep it easy for a while. Change the oil after another 10hrs. No long WOT runs. The gears should be broken in by 25hrs.. Drain it again and then go to a regular schedule.. 25-50hrs.. what ever the oil looks like. If at 25 it looks clean.. go longer, etc.

But easy the first 5-10hrs.. When you spin the prop and it spins free.. it is broken in..

Hope this helps.
Dick

Gear lube
 

No need to test again... Kind of a rude post on your part.
I said the temperature will drop with a synthetic. Yes this is from lack of friction. Synthetics are very efficient that way.

I also said MOMENTARY metal to metal contact will increase under very high pressures (PSI). (Like when the prop comes out of the water and then suddenly re-enters for a split second)
NO LIQUID will stay between two pieces of metal if the PSI is high enough. (It squeezes out, even synthetics)
Solid lubricants (Like Molybdenum or graphite) found in the HP Merc lube will get "stuck" in between the metal and keep the contact/wear to a minimum during these high PSI times.

These times only occur for a split second and do not generate much heat. They do however cause wear on the tooth face.

Also, most sythetic oils are 40-95% petrolium products...