Reply With Quotewhat gears? large prop shaft? what propller? what ratio? who set up lower?
doing some research just curious?
I broke another prop shaft (B-Max upper with Imco lower) last weekend and when we pulled it apart today, we found that the lower gear set was munched also. This is the second time that both the lower gears AND the prop shaft went at the same time. I wasn't even on it that hard when it let go this time. I'm wondering if over time the lower gears start to get munched (from hard running), then could possibly create some sort of vibration or harmonics that could cause the prop shaft to break. I'm thinking that I should PM the lower gear set every 50 hours or so to see if they are starting to get "munched" and if so, change them before they possibly cause the prop shaft to break. Could I be on to something here or is it just a coincedence that both the lower gearset and prop shaft have failed together twice now? :idea:
what gears? large prop shaft? what propller? what ratio? who set up lower?
doing some research just curious?
what gears? large prop shaft? what propller? what ratio? who set up lower?
doing some research just curious?
The gear ratio is 1.30 and I think they are just standard Mercruiser Quicksilver gears for their XR drive. Yes, I have the large prop shaft and mostly run a Bravo 1 4 blade lab 32 prop but will sometimes run a 30 or 34 depending on boost level. The lower has been set up at a local Mercury authorized shop called Pleasure Boat Specialties.
The prop shaft always seems to break just behind the splines where it goes into the gear.
Check your pm's
The gears are coming apart,binding up and then the shaft is breaking?
The gears are coming apart,binding up and then the shaft is breaking?
That would seem to make sense but wouldn't that also try to lock the motor up and kill it if the gears bound up and stopped turning?
That would seem to make sense but wouldn't that also try to lock the motor up and kill it if the gears bound up and stopped turning?
That might be where the broken shaft comes into play.What is it costing you each time it breaks?Im not looking forward to the breaking drives part of my new motor,thats for sure.I heard Imco has a new drive coming out that is going to be very strong.They are testing it and have had really good results with it so far.
That might be where the broken shaft comes into play.What is it costing you each time it breaks?Im not looking forward to the breaking drives part of my new motor,thats for sure.I heard Imco has a new drive coming out that is going to be very strong.They are testing it and have had really good results with it so far.
It's getting costly everytime this happens. The gear set is $490, prop shaft is $650, bearings and misc. parts are around $50 and the labor is $360 for a total of around $1,550 each time this happens. I checked my log book and the gear set and prop shaft lasted about 90 hours before it let go. I will start checking the gear set every 60 hours and replace them if they look worn at that point. At least that should save me the $650 for the prop shaft if that is what's causing it to break. And save me the humilation of getting towed in each time too. :frown:
That would be great if Imco's new drive will handle the torque that today's high performance motors are putting out. My motor puts out 1190 ft. lbs. torque at 4400 RPM and that is eating up the stock Mercruiser XR lower gear set.
have you tought about having max machine set up the lower? imco said they dont expect long life outta there gears
what kinda gear lube do you use?
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