McCrea hydros

[Puddleduck]

Hi, another new Brit on your excellent site, along with my fellow Classic Motor Boat Association member Healey 75!

I have restored a 1956 3 point kneeler hydro 'Thunderbolt III' which was raced in the UK and won the X-Class title in '57 with a souped up Evinrude Storm motor. I know she is a McCrea design from Canada, and built to plans here in the UK, but that's it. Do any of you guys have information on McCrea (not McCrae, I checked the spelling!) or know of anyone running a similar boat? We also have a smaller A Class hydro to identical design in our club.

I do not have the original race motor, but intend to use my 1960 Merc 300 as a user-friendly motor - any ideas how I ring the throttle cable to a fly-away hand grip? I guess I'll have to disconnect the distributor and connect directly to the carburetor.

[Tomtall]

Chris - Nice restore. Welcome to BRF also. There was some postings regarding your hull, but most were concerning more infomation on this Canadian built speed demon. Ed Hatch posted one at this link --- http://www.boatracingfacts.com/forums/showthread.php?t=3873&highlight=McCrea

As far as your throttle hook-up is concerned there has been topic on doing it with the stock linkage here on BRF at one time. Perhaps someone can help you out here on BRF with that thread location.

Keep us updated on your test runs.:)

[Ed Hatch]

There are two sources of the throttle hookup you need for your 4 Cyl Merc. Check Ebay item number: 270297360692. This is sold by Mike Downing, a reliable Ebay seller.

There also is a fellow by the name of Ken Hall who has stainless reproductions of the parts you need, excellent quality from Ken, I bought 3 sets from him some time ago.

If you go to my webpage,http://www.boatsport.org/ and click on the Mark 55H parts list you'll find the picture on page 13A to be self explanatory. Look on page 3A and find the part identified as #2, if your motor doesn't have this part you'll need one since it fits in the inner hole on the part identified as # 20 on page 13A and swings the magneto.

Go to

http://www.btmco.com/ or http://www.portagebaysystems.com/marine/ or http://www.boatracingr11.com/sorensenmain.htm

to find a good quality deadman throttle.

Hope this helps.

[Mark75H]

Or do as I have done and cut the front end of the cable and anchor it in the racing throttle. Don't forget you will need more of the inner wire than the jacket.

[BRIAN HENDRICK]

McCrea was well known in the NE and eastern Canada in the late '40s, early 50s. His plan catalog included a full line of boats from small rowing skiffs to inboard and o/b racers. The catalog I had in the mid 50s had two three point hydros,[and older mono planes] one being a B/C alky boat which looks to be the one in the above pic, and this below one in the 10-56 Boat Sport with Konig driving.
We built the stock AB 3pt in the mid 50s, and it ran well with KG4/7s ,but was overpowered by a M20H.
It had a aircraft fabric deck.
Many of the hulls in the popular inboard class called COD [Canadian One Design] were built from his plans.
Few today recall McCrea, and i have not seen a catalog of his in years. I had always meant to research him more
if I ever got to North Hatley, on the Quebec/Vermont border. Nice to see one of his hulls alive and well.

[John (Taylor) Gabrowski]

I use a Merc 400 on my restored 1970 Chaparral 13.5 foot class F hydro with a bucket seat just to motor around on lazy summer weekends.

I had electric start and choke going too. I bought and took apart a used standard Merc throttle/electrical key and choke control box and on a aluminum plate remounted the key ignition and choke button to below my steering wheel. I use the standard Merc engine plugin as stock electrical system even though the motor uses magneto ignition. Located a 12 volt lead acid utility starting battery to the floor in a box behind the slide in bucket seat (removable on tracks so it can go back to a kneeler boat with ease).

The 2 Bowden wires from the original Merc control were cut off and shortened one for the dead mans throttle and the other for the forward reverse shifter linkage. In my case I locked the engine out of reverse but gave it forward and neutral, but it could start in both (neutral or forward) in any case.

I used the original engine linkage and made a metal bracket to hold the action to the outside of the cowl no different from stock use. This allowed the use of the engine unaltered from inside the cowls as it would be for ski/fishing use of the motor. The throttle action is slower and stiffer but its still a deadmans throttle unit. I also attached a tethered to jacket electonic kill switch to kill the engine if you get dumped but on an F hydro with a Merc 400 on the back giving me low 50 mile per hour speeds for that boat dumping it was not a concern at half the power and speeds you could hang on it.

Cost of the conversion was about $25.00 for the used control module with its 16 foot cables and some of my time to easily configure it. There is no reason for the job to be an expensive one and mine really worked well.

*If your not going to use electric start and choke then omit all the electronics except the tethered to life jacket electronic dump out kill switch. Think safety first. With that the price just dropped too.

I used the standard Merc H type chromed steering bar and racing cable steering.

I posted some pictures of this boat fully rigged and on its trailer somewhere on this BRF website too :)

Hope I have been a help. :)

[John (Taylor) Gabrowski]

I forgot to mention that in choosing a prop get the biggest one in diameter and pitch you can find for your Merc 300 (30 cubic inch 4 banger) (Merc 30H-1s were the racing versions of your ski-fishing engine) because of the gearing and power to weight rations involved with your engine and boat. I also ended up shimming up the engine slightly to ensure the cavitation plate was a minimum of 1.5 inches above the bottom of the boat, with the principle of keeping the water under the cavitation plate and not over it through any force otherwise your not going to get your avaible speed right. Also do not raise the engine too high as you could cripple its water cooling pickup and fry the engine.

I can't think of anything else off hand other than it became an enjoyable weekend cruiser with a 50+miles per hour bang to it but my engine is a Merc 44 cubic inch and yours is a 30 cuber so the performance won't be the same though quite satisfying for the effort.

[John (Taylor) Gabrowski]

Puddleduck: There are other UK enthusiasts on here too like Rod Champkin aka Twister and so on. I know UK s a big country with a load of people but finding out who is around you to help out with their racing knowledge could be a help to you so look them up. They hang around on BRF and could be a source of getting together over there in UK making the scene both exciting and sociable.

Hands across the waters to you from Canada! and it just snowed about an inch here! Arghhhhhhhh!!! :)

[Roy Hodges]

If I am not mistaken, the merc300 was a 40 cube motor , same as a mark 55 , but rated at 35 horses .It seems to me that a merc300 is also the same as my mark35A.

[John (Taylor) Gabrowski]

Roy:

The Merc 300 is the same update casting as the 30H-1 racing block with 30 cubic inches.

It is the same newer block design as the Merc 55H-1 was with the smaller bore.

This newer style of block design went from 4 individual intake inspection ports to the 2 paired combined type.

The Merc 350 is the 40 cubic inch engine which still used the Tillotson AJ and some later ones had Tillotson "KB" carbs with the newer updated Mark 55 block we call a Mark 55H-1 block but for it in racing they had the bigger KA7A carbs for racing along with the H tower and gearcase.

[Mark75H]

300 is a 40 like a 35A

[John (Taylor) Gabrowski]

Mark 35A is a 40 cuber? no different than a Merc 350 with AJ sized carbs,. your probably right. I have had several Merc 350s salvaged for their blocks and cranks.

Mark 55A is not a 40 cuber but a 44 cube engine with AJ carbs. It was the earliest 44 cuber.

Merc 300 is a 30 cube engine. I had two and still have one and its a C-Mod now with a Mark50 crankshaft in it with LeBanco pipes and KC6 carbs on it and pictured here on BRF because of the older NOS Mk50 crank it fit.

[Mark75H]

Correct on the 35A, 300 is still a 40. Merc didn't make a 30 after the 30H. Correct on the 55A, its a 44 like the 58A that came out simultaneously. Neither was first.

[John (Taylor) Gabrowski]

Merc did make uo 30H-1s and well as 55H-1s. I used to have half a dozen 20Hs, 30Hs and 55Hs of which there were 2 - 30H-1s and 2 - 55H-1s. It could be that they were what you called "parts" motors from Mercury with their newer block style and squarish top wide shieve easy pull recoil starts but they came with their original Merc ID plates so that is what they were.

[Mark75H]

I think that most people would understand "30H" to include the 1959 Mk30H-1 sub-variant, which was the last 30ci Merc listed anywhere. I did not say there were no 30 ci motors after 1956. I will say no 30 ci motors after 1959 other than the few 1962 30H's.

[John (Taylor) Gabrowski]

I still have one Merc 30 cubic inch C Modified made from a Merc 300 out of the 2 I used to have. Maybe Merc did something different in Canada like sending Mark 55E blocks sometimes with and sometimes without serial numbers to replace Mark 55H blocks which was also done more than once. Next Merc 300 I lay my hands on his going to have its disassembly pictorial posted here on on BRF.

[Roy Hodges]

was a 40 inch motor with electric start AND alternator . I had one ,bought new in summer of 1957 , serial # 1091992 . A mk 55 S was electric start without an alternator. I calculated that a 40Cube block, to be made into a 30 cubic inch block would need VERY thick sleeves , about .1094 inch THICKER than the stock 40 in sleeves . ( Wall thickness ).......Mark 55E was a fishing motor,as was ALL the 30 & 40 inch motors , except those "H" motors .

[John (Taylor) Gabrowski]

I agree with your clarification on the Mark 55s in particular the Mark 55E. Evidently they sent them out here as substitute for use as Mark55H blocks because the porting was near identical.

I sure would not want to resleve a Mark 55 - 40 inch block down to the bore of a 30, who knows what irregular heat transfer problems would arise.

[Mark75H]

.060" different

[Puddleduck]

Blimey! I only asked a simple question and you guys are off on a bigger one than McCain Vs Obama! Amazing in-depth knowledge - many thanks for the feedback, especially on the throttle hook-up. Ref the propeller I've been given a nice 2-blade quicksilver 23587 A2 - 13. It needs a birthday but otherwise OK - more chance of finding rocking horse poo than racing props for non- through hub mercs here in the UK!

[Roy Hodges]

.060" different......................................... ..................
Figure it again. the Mk 30 has a bore of about 2.1094 (2 & 7/64" . The 40" block has a bore of 2 &7/16". (2.4375")
My last calculation was a DIFFERENCE of .328 of an inch bore. Half of THAT is .164".
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Happy sleeving !

[John (Taylor) Gabrowski]

Puddleduck:

We sure want to help so call us encouragable! Besides your a cousin to all of us here in North America! The colonies if you please! If I didn't say something all my relatives in Newcastle on Tyne would storm over here and beat me about the head for standing by while you put it in reverse and sunk! LOL! :)

Besides after reading much here we might get you enthused about building a 4 carb, 444 version of a Tim Kurcs gasser FE Merc 44 cuber some day? It would wake up more than just the UK countryside with open pipes!

[Mark75H]

No, Roy, the porting on a Mk55 and Mk55H are .060" different ... not "near identical"

[Puddleduck]

Lovely idea John, but the only open pipes you're likely to find in the British countryside are drainpipes! We are cursed with the fun police in the UK - if it looks good, goes fast and make loads of noise doing it, some green-wellied, tree-hugging, bird watching ozone friendly member of the flat earth society will get it banned! :mad:This applies to bikes, cars and boats - bloody dead loss. However my club, the Classic Motor Boat Association, endeavours to hold rallies and meets with our old boats wherever we can - and we like fast noisy boats! Most of our boats are runabouts, but we also have several hydros and single steppers being restored orr replicated - take a look on www.cmba-uk.com BRF contributor twister is our president, and I'm current chairman. I also own a 14ft 1959 LoneStar malibu, an aluminium boat built in texas, and as far as I know the only one outside of the US!:)

[Roy Hodges]

No, Roy, the porting on a Mk55 and Mk55H are .060" different ... not "near identical".................................................. .......................................
I'm sorry, i thought you were talking about BORE size . I do not claim to know ANYTHING about porting. Except that every motor "needs some ". I missed your point , somewhere . I was sloppy, maybe . Sorry