Merc 200H

Mercury Outboard general discussion
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KG-7Q
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Merc 200H

Post by KG-7Q »

Anyone do a rat like this before?
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1949 KF-7, 1950 KG-7, 1951 KG-7Q, 1952 KH-7, 1953 KG-7H, 1964 Merc 200, 1976 Merc 110
RVRDRGN
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Re: Merc 200H

Post by RVRDRGN »

Me likey.
Tom Brockmeyer
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Re: Merc 200H

Post by Tom Brockmeyer »

Very nicely done! And I like the painted logo on your cast iron Merc stand, too! Did you do that?
Lake Lanier, 30miles North of Atlanta, GA
Old Mercury outboard fan... Especially the fast ones!
Mercury/MerCruiser, Evinrude/Johnson & VolvoPenta Technician (After my suit & tie wearing career was done!)
Michael
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Re: Merc 200H

Post by Michael »

That is pretty cool Im anxious to see this run icon_thumbup.gif
AU52N
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Re: Merc 200H

Post by AU52N »

Back when the 250 first came out we obtained a powerhead out of a scrape pile at a Mercury dealer that was on the pile due to gear case problems. Put it on a 20H original style tower and gear case with 16:21 gears. Ran it in a local class of EORC called the Little Feature. Engine was on a Speedliner Corsair roll up. We did very well even against 30H's. Alan still has the engine in his collection.
David
bayoumerc
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Re: Merc 200H

Post by bayoumerc »

like
KG-7Q
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Re: Merc 200H

Post by KG-7Q »

AU52N wrote: Fri Jan 14, 2022 11:30 pm Back when the 250 first came out we obtained a powerhead out of a scrape pile at a Mercury dealer that was on the pile due to gear case problems. Put it on a 20H original style tower and gear case with 16:21 gears. Ran it in a local class of EORC called the Little Feature. Engine was on a Speedliner Corsair roll up. We did very well even against 30H's. Alan still has the engine in his collection.
David
200 not 250 right?
1949 KF-7, 1950 KG-7, 1951 KG-7Q, 1952 KH-7, 1953 KG-7H, 1964 Merc 200, 1976 Merc 110
KG-7Q
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Re: Merc 200H

Post by KG-7Q »

Here’s what is going on it’s going on: A BU Sidcraft Bathtub:
E793701F-9781-40A7-BE90-FC589DB17776.jpeg
1949 KF-7, 1950 KG-7, 1951 KG-7Q, 1952 KH-7, 1953 KG-7H, 1964 Merc 200, 1976 Merc 110
ctpdsr
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Re: Merc 200H

Post by ctpdsr »

I really like the look. Is the Powerhead stud pattern same vs. a MK20? The reason a newer M500 44 powerhead will drop on a 35SS tower is the factory casting has 2 sets of holes for the rear studs. Vintage MK55H/40H towers will only fit the 1950's and early 1960's 40 or 44 block stud pattern. 35SS tower works on both. I think the 25SS had an adapter plate?

Chuck
Tom Brockmeyer
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Re: Merc 200H

Post by Tom Brockmeyer »

25SS should bolt on but 25XS used adapter plate to 25SS tower the first year, then adapter/tuner plate to the short 25XS tower moving forward.

The key is SS vs XS here
Lake Lanier, 30miles North of Atlanta, GA
Old Mercury outboard fan... Especially the fast ones!
Mercury/MerCruiser, Evinrude/Johnson & VolvoPenta Technician (After my suit & tie wearing career was done!)
ctpdsr
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Re: Merc 200H

Post by ctpdsr »

Actually this project is a KG7/20H vs. 25SS question. I am a 2-cylinder novice, but think the 22cid powerhead stud pattern is different than the old iron. Did that start with the MK28 and early 200/250? This looks to be a KG7H or unconverted 20H tower.

Chuck
Yellowjacket
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Re: Merc 200H

Post by Yellowjacket »

ctpdsr wrote: Sat Jan 15, 2022 5:36 pm I really like the look. Is the Powerhead stud pattern same vs. a MK20? The reason a newer M500 44 powerhead will drop on a 35SS tower is the factory casting has 2 sets of holes for the rear studs. Vintage MK55H/40H towers will only fit the 1950's and early 1960's 40 or 44 block stud pattern. 35SS tower works on both. I think the 25SS had an adapter plate?

Chuck
SOME 35SS/402XS towers have four holes in the back of the tower and will fit both generation 4 cyl poweheads, and some don't. I have two of those towers and both have OEM Merc Serial plates on them. The one that only has 2 holes and fits only the later powerheads is from a later 35SS. I bought the whole motor and took it apart and still have the powerhead and it was original to that tower so clearly some didn't have 4 holes from the factory. The other tower I bought with an early 500 powerhead on it and that tower has 4 holes. There was some talk at one point that the 4 hole towers were made so that they could be replacement parts for 55H engines and that they then only had to produce one tower for both new 35SS and also for earlier replacement spares. Not sure which is the earlier tower, but the 4 hole tower is S/N 79A205 and the 2 hole tower is S/N 80D228 which was from the later 35SS. The 35SS wrap has the model number over brown stripes so it has to be an early 80's motor. Hope that helps.
AllanF
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Re: Merc 200H

Post by AllanF »

The 22 cube powerheads - up to 1965, have the same bolt pattern as the 20 cu inch motors. They bolt right on to a KG,KF,KE or Mk20H for a "Rat Racer".
22 cube powerheads from 1966 and later use larger dia. studs and the back two bolts have a different spacing.

Nice conversion! I like the shift lever is still there! Any problems with driveshaft engagement being too short - especially with the lower cowling installed???
I would love to have the old driveshaft housing and gearcase for a project!

Allan
KG-7Q
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Re: Merc 200H

Post by KG-7Q »

AllanF wrote: Sat Jan 22, 2022 12:47 am
Nice conversion! I like the shift lever is still there! Any problems with driveshaft engagement being too short - especially with the lower cowling installed???
I would love to have the old driveshaft housing and gearcase for a project!

Allan
Allan,
Still working out the details with drive shaft engagement but in the end it will be fully engaged since I have a male to female extension to make a KH7/Mk15/Mk20 a 15” to 20” motor.
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1949 KF-7, 1950 KG-7, 1951 KG-7Q, 1952 KH-7, 1953 KG-7H, 1964 Merc 200, 1976 Merc 110
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