Tom: Please check your post for my response to your requesting information regarding your motor. Feel free to ask any more questions you might have.
Ron- Glad you jumped in on the post. The two sources I have list the '55 as being based on the Mark 20/KG7 (I checked the tech specs on this site as well as oldmercs.com). Both sources listed that the Mark 25 powerhead wasn't used until the WM-7A models. Was there perhaps a mid-year switch in 1955 to the Mark 25 powerhead..or do both of these sites have erroneous info?
JP: Negative, they must be wrong as I have owned about 6 WM7's & they all had the single fuel line & were equipped with a fuel pump. The Mercury MK20 ran a double fuel line with a crankcase "air pump". I also have a original Wizard Dealers Parts Manual which has the illustrated drawings, it shows the 55 as a single line only, serial #'s ran from 826920-830919 & 887979-888004 inclusive. Also some 55 WM7's ran the MK20H center roller bearing crank but the only way to tell, is to take the powerhead apart as they ran the stock flywheel & it is not worth that on a good WM7.
That's good to know....I have updated my notes. I believe both websites got their information out of Peter Hunn's Old Outboard book, which also states the '55s were based on the MK20/KG7. Perhaps Peter Hunn was referring to the MK20H build that you described below, but that doesn't explain his reference to the KG7 LU?
The Wizards were always kept BEHIND the Mercurys one step as Carl did not want them to be a equal to his latest inovations. They sold for less $ & so he did not want them 'outpreforming" his Mercs. The last lower unit used on the "non shifting" 57 Super 10's NEVER had the "clutch" prop, but rather the smooth prop shaft & shear pin, so even tho the rest was the same as the KG7, the latest engineering improvement was never allowed on the Wizard. Also the clamp brackets & swivel assembly were made by Meta Mould, a Merc subsiduary???????, & were of a rougher texture & I am sure somewhat inferior in strength & cost although I have never seen any that were cracked or broken. Also the Super 10 Wizard never put out quite as much power due to only running a 4 cage reed block, rather than the 8 cage bigger breathing one used on the KG7, along with a smaller carbureator, all designed to "detune" the Wizard. Also this allowed Carl to "unload" a lot of parts that remained from his previous year model Mercurys. You will also notice that the WM7 & WM7-A's used the same rear water jacket cover as the MK20-25 but the "mount holes", were never machined out totally as they were not needed due to the simpler Wizard cowlings, & I might add which were actually better as the powerhead was much easier to service. Also the front four holes on the crancase were there but not threaded due to also not needed the front cowl mounts. Once you actually get into these Wizards & study them, you will see many similarities & differences, but basically the Wizards were the Ford & the Mercurys were the MERCURY, or a Mustang & a Cougar!!!!!, just a Step apart as these cars were, sort of "Kissing Cousins" is how I describe them. I do prefer working on the Wizards over the Merc's as they are just simpler & more & can certainly be updated with a few Merc parts such as the bigger reed block & carb etc to perform on the same level as the KG7, also they, at lest the Mercury produced Wizards are much harder to find as they were never produced or sold in the numbers that the Mercurys were. I love Peter Hunns books but do not always believe all you read, note page 55 of the Golden Age Of Racing outboard edition. There you will see a picture of the 1957 Mercury MK25XH Prototype racer I owned, the article describing it is on page 57 & 58, it says Reportedly 25 were built, WRONG, there were a total of 6 of the lower units built 3 with 1-1 gears & 3 with 14-20 gears & each was somewhat different from the other, they were tested by Jack Leek in Washington State with a MK20H powerhead to determine the best one, then all were to be returned to Mercury & destroyed, Jack kept the best one & it is the only one to survive. Peter just went with the best information he had, at the time which on later research, sometimes new facts were brought out.
Hey There, I make decals for toy Mercury outboards and am trying to make up a set for a rare 1954 model with a golden face plate.
The face plate has a K in a circle and under that are three lines of type that I can't read?
If any one knows what they say i'd appreciate it!
This is the motor...