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Author Topic: 1930 Johnson PR-50 Hydro Racer  (Read 7195 times)
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AusF233
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« on: July 02, 2015, 06:05:00 PM »

Have just added one to my growing collection and am looking for any info.

The PR-50 is a 30CI opposed twin with rotary valve fuel supply system. Initial research suggests they were generally run on Alcohol, but may have run on Petrol as also, possibly with a change of carb. The drive tube and transom brackets on this particular one have been remanufactured from steel, and the gearbox/prop appear to be aftermarket, possibly a Hubbell. The exhaust is directed straight out of the barrels via aluminium exhaust vents approx. 4 inches long. There are no mufflers.

It came with the original drive tube and transom bracket, which has a fractured steering swivel. The previous owner suggested the original components were very heavy and prone to failure, hence the reason a steel alternative was fabricated. Whilst I can't argue any of that the fabricated parts are designed for a much shorter transom assembly suggesting boat design was probably the main driver for the change.

Was apparently race by a Bert (Burt) Jones and featured in TOMM (The Old Machinery Magazine) some years ago, but I cant find records of either.

It's not 'in one piece' at the moment so it will be a while before pics are posted. Absolutely nothing wrong with it, in fact it's been fully restored and disassembled just for transport.

In the meantime if you have any information you are able to share, it would be greatly appreciated.
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AusF233
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« Reply #1 on: July 04, 2015, 12:59:10 PM »

A few have asked off line so here's some pics.

As purchased, prior to dis-assembly and packaging for transport.



Currently fitted with an Evinrude rope start that will be replaced in due course. Second pic is what it should look like.





The carb that's currently fitted, presumably to allow operation with petrol/oil mix instead of Methanol ... also needs to be replaced with an original.



The fabricated drive and transom assembly. The workmanship on this is outstanding. The super short drive section suggests application was a vintage Hydro of sorts.





The aftermarket (possibly Hubbell) racing gearbox and prop. It's standing upright in this pic ie there is no skeg as such. From what i understand aftermarket gearboxes such as this were not as strong as the originals, they were however more streamlined ie less drag.



Overnight I managed to pin down a year range (2003-2005) for the feature in TOMM which is said to include details of the original owner and some of the race history. I'll be on to the editors next week.

Regards,
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AusOB_Collector
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« Reply #2 on: October 24, 2015, 09:28:43 AM »

Hi Spiro
Did you ever get anywhere with finding more info about the racing career of this motor?
It's quite interesting to find one of these Johnsons over here in Australia, let alone to find info about it being used for racing etc.

Cheers
BP
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AusF233
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« Reply #3 on: October 30, 2015, 12:34:50 PM »

Hi Boyd,

Unfortunately I've not been able to make a lot of progress thus far. I know Bob purchased the PR50 from another collector (Noel Wenzel NSW - now deceased) and that Noel had purchased it from his friend Bert Jones (also now deceased) who had raced it over several years.

I eventually managed to get a copy of TOMM #110 2003. It comprised a photo taken at a putt-putt rally with a few words below acknowledging the owner and referencing the rotary valve, but that's it.

I'm yet to get on to Doug in the States about the parts. It would be nice to replace the rope pulley, coil (with an original), carby (race edition), the fuel tank and right hand barrel when looking from the carb end. The alternative is to leave as is, which is how it was raced, so I'm still undecided as to which way I'll go.

Regards,
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AusF233
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« Reply #4 on: August 04, 2016, 01:17:28 PM »

Not a lot of progress to report on this one, but it is moving along slowly.

First up, a copy of the pic of it from the 2003 edition of The Old Machinery Magazine. thought I'd pop this up because there wasn't many pics of the assembled outboard posted previously.



Have started cleaning up some of the bolt on parts. Here's a few of the gearbox as a sample of what's being done.







I managed to find some NOS Champion R1 plugs in the US and had those shipped to me.



I have also managed to find a correct methanol carb and spent a lazy Saturday afternoon cleaning that up.

First pic for size relativity. The 2" throat seems excessive to me for a 24hp outboard, but who am I to argue with the experts?













More in due course.

Regards,
S

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MERCMAN
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« Reply #5 on: August 05, 2016, 08:22:54 AM »

Spiro,
Your beaut little motor is sure taking shape. As the gearcase has no skeg, I immediately thought the hydro would have been steered with an independent rudder, as outboard hydro's often are. However, in another photo I noticed the motor is fitted with an outrigger steering bar. I wonder how they managed to have the boat go in a straight line, let alone go around a turn buoy?

Do you know John, D'arcy or Brian Troy? Their Father Harold (now deceased) may have been able to tell you all about Bert Jones. Perhaps one Harold's Sons can fill in the missing pieces?

DT use to own a race boats with Brian (88). May be DT has Brian's contact details? I can also provide you with a path to locate John if need be.

Oh yeah, what a great name for a Carbie!

MERCMAN.
« Last Edit: August 05, 2016, 04:34:17 PM by MERCMAN » Logged

It's perfectly safe.. unless something goes wrong!
AusF233
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« Reply #6 on: August 05, 2016, 11:38:36 AM »

G'day guy,

I also had questions about steering and tracking and the only thing I could come up with is that the leg must have sat further into the water back then ie against what we would expect in a high speed application today. By sitting deeper, the section immediately above the gearbox and below the cav plate may have contributed to rudder action, but I just don't know.

The is a little skeg at the fore of the gearbox. Other that that, what you see is by design, not a modification.

Bert Jones was definitely around in the 80's so there is a chance the bloke you mention may know of him. I haven't mixed in those circles so don't know any of them, so if you can make a few calls to find out what they may or may not know about Bert and this little outboard it would be great.

Thanks & Regards
Spiro
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MERCMAN
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« Reply #7 on: August 05, 2016, 04:28:51 PM »

Spiro,
PM sent.

MERCMAN.
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AusF233
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« Reply #8 on: September 22, 2016, 03:42:51 PM »

Learning lots about this thing as I go.

Rotary valve is after-market and same may apply to the crank-case also. Not overly fussed about that, because it's expected that race motors will be fitted with non-standard equipment ie racers used whatever was available to keep their motors going. That said. many after-market parts eg Hubbell, Quincy etc were generally of a better design/quality and delivered improved performance, hence they are more sought after than factory originals, at least amongst race enthusiasts anyway.

Have also found that the heads are off a Johnson PO-15. AOMCI members have advised that was a common mod delivering increased compression. Another interesting mod is replacement of the original single coil in the magneto with 2 separate coils. These ones are Victa and fitted by Bob, who was the previous owner. However the Americans do the same mod with near identical coils otherwise branded and claim that the benefit is a much stronger spark at the plugs. Don't know how true that is (I've got nothing to compare) but am happy to run with it.

I was fortunate that an original P-50 / PR-50 rope sheave appeared on eBay US. Needless to say, I purchased it and it's now on this motor.

Still a ways to go, but here's some photos.







Regards,
S
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