56ci OMC realistic power

[Hounddog]

somebody is getting a little bit mixed up about a 70hp oval port on the dyno in 2004 !!!

I would not be surprised if I was. That was several years ago and the complete process took about an hour. The owner had the outfit there for a bad cdi box. They had the motor on the dyno to test the new box. They were talking about the small carbs. I happened to be there working on our SST 60 race boat. The owner of the marina wondered if the 60 carbs would make a difference on that motor. I had my break in motor 60 carbs with me that is why I knew they had 75 jets. They took off the original carbs and I put on my 60 carbs. That was all we did. We did not do any more and the motor ran fine.

[ferdthe4]

Regardless of what year you did the carb swap and dump test the info is much appreciated. Modifiedoutboard what the heck etec are those reed cages off of been trying to back search the part numbers off the ad to see what engines they were on with no luck.

[filthy phill]

Regardless of what year you did the carb swap and dump test the info is much appreciated. Modifiedoutboard what the heck etec are those reed cages off of been trying to back search the part numbers off the ad to see what engines they were on with no luck.

If you knew anything about the oval port you would understand it matters a great deal about that dyno test. The engine was NOT a 70hp. It had the small carbs therefore just the 60hp version. The carb swap for the sst60 carbs just took the motor to the same level as the proper bigger 70hp black top carbs. If you only have the small carbs it is not a 70hp. I have enough sets of black tops here.
Far too much false information about oval ports and their carbs and blocks and heads and porting going around. In the states too many people swapping decals about makes everyone think they have a 70. Mine was 60 until I got the bigger carbs. It made massive difference from low to top end.

[filthy phill]

Those reeds are on 2011 .15hp. 25hp and 30hp e-tecs.

[MODIFIEDOUTBOARD]

Regardless of what year you did the carb swap and dump test the info is much appreciated. Modifiedoutboard what the heck etec are those reed cages off of been trying to back search the part numbers off the ad to see what engines they were on with no luck.

The late model 56ci Omc triples 70hp went to a 1-7/16 dia carb after OMC realized the 1-1/2" was not necessary to make 70hp.
The late model 2 cyl's continued to use the 1-1/2 big carbss and will fit directly and look identical to the 1-7/16 carbs on the outside.
Using SST 60 JETTING Will get you close for a start.

The etec reed cages are a modern BRP version of the ancient cages used in the 56triples.
Square ports eliminate need for porting. They will improve air flow significantly vs old cages.
Get some reeds and jet up a couple of steps �� modify front and jet up more��

[Mike Wienandt]

I have built over 15 national championship winning SST 60s. The last 8 years I have run been about 100 - 102 hp at the crank. We dyno with the exhaust housing and gearcase so we match correct exhaust back pressure. The mod engines I make for lake racers or X class inflatables are now up to 118 hp. This is with stock SST 60 carbs. I'm working on one right now that is very over due. Porting includes finger porting, Boost port reground, A lot of grinding in the transfer ports, Exhaust port reshaping and timing edges of all ports to my own specs. Stock head with welded smaller thermostat hole, then re-machine to smaller ccs and angled squish band added. SST 60 reed pedals and grinding in intake and matching the case. Bored to .030 over with Line2Line coated pistons from Pro Marine. Stock SST 60 tuner. We have over 350 dyno runs doing development work on these. Dyno all computerized so no bull crap. Can't argue with the win history.

[Mike Wienandt]

there are two main kinds of carbs, What I call 2 jet and 3 jet. The 3 jet is from SST 45 and also older 50 ci engines. I have never been able to make 56 ci engine run on the 3 jet carbs correctly.

[Mike Wienandt]

Was reading one of the other posts, The engine has a bad harmonic vibration that you must avoid to prevent damage of the engine. 4000-4300 it shakes so bad it screws up the fuel in the float bowl and the engine will run lean. Also at 8000, DON'T GO THERE. Run best up to 7600-7700. Everyone that I have seem go to 8000 will stick pistons.

[hupiveneilija]

there are two main kinds of carbs, What I call 2 jet and 3 jet. The 3 jet is from SST 45 and also older 50 ci engines. I have never been able to make 56 ci engine run on the 3 jet carbs correctly.

Could it possible be differential in emulsion tubes that causes this? They mix air&gas different. IMO those big variations of mainjets in 56series carbs might be about those tubes been different from carb to another.
Mains differ from 50 to 65 between them. Im talking Bp carbs now.

[LittleCharger]

I have built over 15 national championship winning SST 60s. The last 8 years I have run been about 100 - 102 hp at the crank. We dyno with the exhaust housing and gearcase so we match correct exhaust back pressure. The mod engines I make for lake racers or X class inflatables are now up to 118 hp. This is with stock SST 60 carbs. I'm working on one right now that is very over due. Porting includes finger porting, Boost port reground, A lot of grinding in the transfer ports, Exhaust port reshaping and timing edges of all ports to my own specs. Stock head with welded smaller thermostat hole, then re-machine to smaller ccs and angled squish band added. SST 60 reed pedals and grinding in intake and matching the case. Bored to .030 over with Line2Line coated pistons from Pro Marine. Stock SST 60 tuner. We have over 350 dyno runs doing development work on these. Dyno all computerized so no bull crap. Can't argue with the win history.

Mike for the X motors you build which block do you prefer the oval port or Bridgeport as your base...cheers