Building a Super Mod 2 cylinder Mariner/Yamaha
Because of the 70 CES Yamaha Thread several people are interested in building one of this power heads.
The Motor
In the states it was the Mariner 48, 55 and 60 hp, 2 cylinder, 15 inch, 1.84 or 1.71 gearcase, Yamaha made.
In Mexico and Canada it was the Enduro or Yamaha brand.
The motor was sold world wide as a commercial motor. Very sound and well build.
You can still get new parts thru Canada and Mexico.
Unlike the 70 hp Yamaha this motor has a solid steel crank, bolt on rods, twin carbs and a unique double exit exhaust system.
You can get Boyensen reeds for them.
You can use a 70 or 90 hp factory power trim on the long shaft version.
You can use Pro 50 power trim on the short shaft version
You can use the old in-line 4 and 6 cylinder Mercury power trim on either version
Stock Performance
We have only had one to try. It was a 55 hp Mariner long shaft. On a Delta and a VooDoo
high 50's with NO MODS at all.
What you should be able to get MOD
80 to 90 hp
Cylinder head MOD
There are one or two people on this site that can make small chamber heads for these. Being a commercial motor, the head is not a performance head. A performance head will make a big difference.
The Crank
Unlike the OMC 45 cubic inch crank which weakens after being reworked, this crank does not. It can be stroked to perfect spec and blue printed.
The Exhaust Chambers
I am sure someone will come up with some performance ideas for them.
Cost
Lots of low cost stuff out there, good bang for the buck.
What is different about the exhaust tuner?
Yamaha parts.. are still avaliable
http://www.boats.net/parts/search/Ya...ING/parts.html
NOTE: YAMAHA DID NOT MAKE THE 15 inch model to my knowledge.
nothing new under the sun
Quote:
Originally Posted by
Fast Fred
the exhaust on the 60DES was separate from each other, twin cow bell. held all 750cc records.at about 5500rpms about 40hp slams into the power band. :cool:
Yamaha SUPERJET 701 TWIN
comes stock with individual tuners similar to the 60 twin, makes 73 hp , with twin 38mm carbs and several other similarities to the 45.
Difference is in the late nineties RD Performance figured out a exhaust the worked from 3,500 rpms up. I was fortunate enough to talk to the engine guru there several times. He said they filled up a 40ft trailer with test pipes. They end result was a pipe that bumped a stock 73 hp Yamaha up to 100hp. In 1999 and 2,000 RD dominated every heat of the Worlds with that pipe. On a ported Yamaha they sell the pipe in a kit and gaurentee 140 hp from 7,400 to 7,800 along with arm wrenching acceleration. They said they could make more power but the drivers want acceleration. I have one of the pipes never used it or RD race porting specs. Just running rec specs. Stock Super Jet Exhaust opens at 89 deg ATDC Transfers open at 120/118 deg ATDC .
Here is a new old stock 15 inch mid. Also fits the 90 hp Yamaha
http://www.ebay.co.uk/itm/YAMAHA-MAR...item58914982f9
DRIVE SHAFT HOUSING
FOR 55 / 60 H.P.
STD SHAFT ( SHORT)
LATE '70, 80 & 90
2 CYL ENGINES
ALSO FIT SOME MARINER 55 / 60 HP
NEW OLD STOCK
Yamaha part no : 687-45111-00
Mariner part no: 1587-7163M