Autoprop Rebuild

[Frankly]

H5 BB sometime after the remachining during one of my bearing replacements. The original is now 25 years old and working fine.

Frankly

[scfoster]

Originally Posted by Dockhead

New races come with the bearing kits for the H5 with loose balls too:


Attachment 232238


H5 Ball Bearing Kit


Or maybe you have the old seawater lubricated type?

No. Mine is not the seawater lubricated unit. Called Rod at King Propulsion, the USA distributor. He confirmed the H5 has never had a replaceable ball bearing race. The picture shown on the website is for an H6 and he's going to fix that with a disclaimer.

Thanks for questioning it though. Never hurts to check the facts.

[Mickeyrouse]

I would encourage prop inspection annually. I realize the 3 blade models are completely different from the two-blade “ classic” I cruised with for about 15 years but one thing they have in common: they’re in the marine environment. I went a couple years between haul-outs. Barnacles grew just the same. They are inconsiderate little devils and don’t care about growing in balance. Since I didn’t realize they were sprouting- inspection for years showed no growth, no doubt due to reduced salinity, the increased imbalance was imperceptible on a week-to-week basis, meaning uneven wear at the blade roots. Which meant slack, and REAL imbalance. Eventually a couple engine mount studs broke, not noticed until I re-powered. Sent the prop back for service during refit, but was not balanced properly. The vibration that ensued was not related, by me at least, to the prop. All kinds of things on the engine vibrated off, including broken mounts again. Replaced the prop and mounts (again). I finally realized cleaning the prop (snorkel job in warm weather) could do that, but keeping the prop greased was another matter. Since our local boat yard has closed, a lift with the capacity we need is a couple days away each way. So last haul-out, I went back to a fixed three blade.
Funny thing is, I never could discern any improvement in sailing performance with the Max Prop. I was hoping for a full knot, and top speed never seemed any better. Likely it helped in lighter air, but unless one is meticulously logging loading, point of sail, sail trim, sea state, wind speed, hull cleanliness, and all other possible relevant variables, and then comparing before and after performance under comparable conditions, it was impossible to make a firm statement about performance. I’m sure it helped- but how much? Considering the tens of thousands of miles we have sailed our boat, I’d have to say may be a quarter knot improvement over all- not much for the investment in two props, the replacement drive shaft, expense of original installation, returns for maintenance, annual service, etc. etc.
One clear advantage: When you drive your boat on to a mud bank, full thrust in reverse is worth something.

[scfoster]

I have to give Rod at King Propulsion in Virginia Beach, VA kudos for the level of service. He answers the phone and has always responded to emails within 24 hours.

The kit I ordered didn't come with new tab screws but instead came with tab washers. Emailed Rod and he got 3 new ones in the mail to me the same day, along with a grease fitting. It's when things don't go so well and the vendor fixes things quickly, that makes all the difference.

Turns out he's the the guy in the Bruntons YouTube videos.

[Frankly]

At 2,500 RPM my fixed 3 blade produces 5.5 knots and 6.25 with the 3 blade AP. Sailing there are just too many variables to make an accurate assessment. Because I usually go 3 or 4 years between bottom jobs, I repaint my AP most every year. I have the tools to pull the prop with the boat in the water. Easy but don't try this in deep water. You and that AP are headed straight to the bottom when that thing comes off the shaft.

Because of the significant increase in mass/ rotational inertia new rear motor mounts every 7 or 8 years are part of the equation. There is no apparent shaft vibration but it does work on those soft Yanmar mounts.

As often mentioned one of the real pluses of the AP is motor sailing. 30 years with the US Navy scratched my nasty weather itch. Light air, IP, all sails,1200 RPM makes for smooth passages for me and mom.


Frankly

[scfoster]

Finally started the reassembly process and ran into a snag. Even though the #3 blade assembly looked the worst, turns out the issue is with #2.
Once assembled and not even torqued down, the #2 blade will not fall under its own weight. Can feel a roughness when rotating the blade. Have to back the nut way off to get it to fall under its own weight but then the blade is loose and can be rocked.
When the boat was hauled out, one of the blades definitely did not rotate freely. Thought it was #3, based on the observations after disassembly. Guess I was wrong.

So, looks like a trip back to Blighty to fix it.

[scfoster]

Got a quote to do the burnishing for $95 in the UK. The shipping round trip is going to cost more than that.

Again, kudos to Rod at King Propulsion for the super-fast service.

Decided to send all the parts back to the UK, to have them assemble and torque everything. The reason being that I don't want to get it back and have something else be the cause of the #2 blade binding. Don't think so but don't want to have a back and forth when splashing the boat is imminent.

[C420sailor]

I made my own tools for the H5.

First was a puller. I took a piece of 3/16" steel plate, drilled three holes for mounting to the prop (M6 bolts, use the anode as a template) and then drilled a larger hole dead center of all three. At this center hole, I welded a single steel nut and sent a grade 8 stainless bolt (M8 or M10, I believe) through. Pulling the prop is as simple as loosening the prop nut until it is just about flush with the back of the prop hub (but not fully removed), bolting the puller to the hub, putting some tension on the center bolt (don't Hulk it), and thwacking both sides of the forward portion of the prop hub with two mallets. Ping! Popped free. No need to mess with a three jaw, very cheap to build.

Other tool was made from a Husky 7/8" 12pt socket. I ground it to leave pegs at the 12, 3, 6, and 9 o'clock positions. Those pegs should coincide with the thicker wall portions of the socket. Grinder at first, then hand file. It'll take some time, but you'll be able to fashion the pegs in such a way that they will fit both the caps AND the blade nuts. A quick blast with the cordless impact made quick work of them.

My blades don't fall perfectly under their own weight. I have some mild brinelling as well. The prescribed torque values weren't working for me (too much wobble) so I reverted to my old mechanical ways. I torqued the blades somewhat tightly in order to fully seat the races, then backed off and re-torqued. I ever so carefully torqued (a few degrees at a time) until the blades no longer visibly or audibly wobbled, and no further. They actually became easier to move after sitting for a few days---I think the hard seals take some time to settle in, and are very draggy at first. I experimented with backing off on the torque, and it didn't really help with blade drop--it merely added wobble. Must be the brinelling.

Rod is top notch. I picked my rebuild kit up from him at his home in Virginia Beach. Very nice guy, will go out of his way to help.

[scfoster]

Received and installed the rebuilt H5 Autoprop.

After shipping to Bruntons in the UK, they machined and burnished the bearing tracks for all three blades and hub. Had them assemble the parts; made sense since they do it all the time. Total cost was under $200. Return shipping was $126. They even threw in an extra zinc with screws.

Very happy with the results and the service. I can't recommend Rod Sampson at King Propulsion enough. The service level was top notch.

Installation was very simple. Removed the grub screw from the prop hub. Cleaned the shaft, including the keyway. Ran the prop shaft nut through all the threads on the end of the prop drive shaft, just to make sure the threads were clean with no binding.

Removed the prop shaft nut and marked the location of the divot on the side of the nut with a sharpie pen, where the hub grub screw would contact and secure the nut. The purpose is to see where the divot is located, to align it with the grub screw hole in the hub, when assembling.

Put some grease on the shaft, installed the key then slid on the prop hub, aligning the keyway.
Screwed on the prop shaft nut and continued to tighten until the nut bottomed on the inside of the hub.
Checked the mark on the end of the nut and its alignment with the grub screw shaft in the hub. Continued to tighten/torque the nut until the marks aligned. Checked that the divot in the nut was aligned with the grub screw shaft using a flashlight. Installed the grub screw with loctite on the threads.

Installed the zinc on the end with three plastic screws and loctite. Installed the rope cutter on the shaft and that was it. Whole install process took less than 30 minutes.


https://www.ab-marine.com/PDF_downlo...s%20manual.pdf