mariner piston kit

I'm looking for a .030 (.75mm) over piston kit for my 1978 Mariner 40B. I've found some Yamaha kits that are the right size, but are they the same? Will they work? The numbers are 6H4-11636-00-00 for a .50 over, and a .75 over that is the same kit but identified with 100-260-06.

Thanks, Rick

I know that this is a though one, but I'd appreciate anything you've got. I've done some more resrearch since my first post. From everything I've found, Proparts 11636 piston kit seems to fit. It list to fit '79-'97. I don't know of any differances between a '78 and a '79. Can anyone sort this out for me?
Thanks Again, Rick

I have a 1977/78 Mariner 55 two cylinder outboard which was actually built by Yamaha (sold by Mercury apparently but there is another story). All the Yamaha components are the same except for the trim unit, the starter motor, neutral switch and whatever else I haven't found yet. I would be very surpised if the equivalent Yamaha parts are not the correct replacement ones for your Mariner outboard. I have been blessed with the parts manuals for both Yamaha and Mariner 48/55/60 outboards so for me it is relatively easy to cross reference part numbers to each other and aftermarket replacements. If you can get your hands on the parts guides for your specific outboard that will help you out.

There is a parts catalogue on this website, you'll need the serial number for your engine to decide which serial range your outboard belongs to.

I think you're right, apparently there is another story. I have a manual and parts catalog for my model. I also have a parts catalog for a 1978 40A Yamaha. They look identical. The Quick Silver carb kit I bought had a Yamaha label under their's that matched up. Other than things like that, you can never really cross reference the two. Other than the parts catalog ,that I miraculously found online, you can never find anything on Yamahas built before 1984. I wonder what the story is. With some work, I've always been able to find Mariner parts. This is the first time that I couldn't, and I can't get an exact match for the 40A numbers. Yamaha numbers are so confusing with all of their prefixes and sufixes. Like I said, I can find pistons (after market) that replace Yamaha kits with the same core numbers, but with out any way to cross reference, I don't know what Yami models they replace, and of course, the pre 1984's are unmentionable. I think the only way to find out is to buy some, and if they don't match up, I'll ship 'em back. Thanks alot for the imput!
Rick

Mariners were built for Mercury by Yamaha. They were exact copies of Yamaha's own,older models,painted them the Mariner colours.
Yamaha entered the US market about '84 so most online sources are US based and don't have schematics for earlier Yamahas sold in Europe or the Southern Hemisphere.
If Graham Lamb is floating about he would give you the full story.
Apparently they built Mariners up to '92-'93

The cylinders are bored and the pistons are in. I thought I would post this in case anyone else needs the info.
Pro Marine is the only makers of piston kits for 2 Cyl Mariner and Yamaha outboards. They make a std.-#11631 and a .020 over-#11636. I bought mine through Mastertech.