OPS .21 Supermarine

[Josh Stollfuss]

Does anyone run an OPS .21 supermarine? This is the one with the front exhaust, not the side exhaust. If so what carb are you running on it? This engine comes from OPS with a slide carb like buggies and trucks use. I'd like to run a rotary carb like we normally use on our marine engines. Any suggestions?

Josh-

 

[anthony_marquart]

For some reason this engine has not become real popular. I remember a lot of hype when it came out though. Maybe the carb for the side exhaust engine would work. That or you could use a Perry carb.

 

[Josh Stollfuss]

Yea I've never seen anoybody use one around here. Anybody have any experience with one of these?

 

[Jerry Muro]

There is one running in disrict 1 namba that runs very well,it is running with a G 20 OS carb and a OPS 3280 pipe. The boat is very competitive in 20 mono. great little engine for the price. JMO

 

[boatworx]

I run this engine and i use the OPS79300 carb & 3280 pipe. This carby is 9mm bore and has r/c mixture control and

has a lever for direct push pull from radio box no need for any bellcrank.You need a conversion ring as this carb has 14mm base and engine is 15mm. I have 2 mono's which are on the pace with MAC's and are fitting one into a 21 eagle and they are available.

Brian

 

[Tim_Duggan]

I can confirm Brian's OPS powered mono is in fact a bullet!!!!!!! I witnessed it first hand last weekend. Very impressive performer.

 

[sport hydro]

I run one in a SD2 mono. I am using the slide carb with no problems. When the boat is trimed right, I can compete with some of the fastest MAC and CMB monos in the area. I have the OPS muffled pipe that comes with the motor set at 8 5/8".

 

[jimv]

I run one in a SD2 mono. I am using the slide carb with no problems. When the boat is trimed right, I can compete with some of the fastest MAC and CMB monos in the area. I have the OPS muffled pipe that comes with the motor set at 8 5/8".

I used one of the side port OPS .21's a while ago in a home built .21. The carb that came with it was a Perry carb. Never used that. Used a couple different K&B .40 carbs. Very simple, just a simple needle adjustment. I did some heavy porting on the engine to numbers exceeding what are on the engine today. Made my own connecting rods (similar to RPM) that I would replace after a day at the lake. At the time, the RPM rod bushing would come loose in that engine. Ran an Irwin pipe with pressure to the tank. It really matched the engine's characterisitics. Made my own heads, playing with squish band shape, bowl shape and clearance. Ran best with a tight squish. The best it would run was with a little detonation in the head. It would stretch the plug element a little each run. I'd get about 3-4 runs per plug when it was right. The fuel was Logge 60%

At the time these engines did not run well as sold in stock form. OPS made adjustments to the timing and I understand they are nice motors now. However, there is more to be had if you are adventurous. If you can find one of the old K&B carbs from the 70's you might give it a try. Very simple to set up and make work.

Jim Vota

 

[Josh Stollfuss]

So this engine by design likes a little longer pipe length then a Mac or CMB? I say this becasue my Microburst with a MAC .21 has the pipe set at just over 8 inches, and one of the recommendations on this engine was 8-5/8 inches. Is this due to the front exhasut and the 180 deg bend in the header? Or just the timing in difference on this engine itself?

Josh-

 

[Heartbeat]

So this engine by design likes a little longer pipe length then a Mac or CMB? I say this becasue my Microburst with a MAC .21 has the pipe set at just over 8 inches, and one of the recommendations on this engine was 8-5/8 inches. Is this due to the front exhasut and the 180 deg bend in the header? Or just the timing in difference on this engine itself?

Josh-

Josh

Mine likes the same pipe as my Nova long stroke.

Mike

 

[Josh Stollfuss]

Mike, What length is that?

Josh-

 

[hhn]

We run this engine in NAMBA District I We have an OS 4D Carb on it with a Kalistrative Remote Needle. The reason for the remote needle is just spacing in a very small area. You could just as well use the OS 3rd Channel assembly. We are using a Cooper silent pipe and 65% Nitro. Keep the head clearance about 10 to 12 for easier starting using a McCoy MC-9 Plug and you have a very reliable engine that really puts out with the best of them. We used the same set of bearings for over 3 years of heavy competition and the piston & sleeve is still in remarkably great condition. Once properly set up ou could not ask for a better engine & no modifications are necessary. This is one that OPS got right.

 

[tmunn]

I think I just bought one of these...

could someone post a picture of how this engine is installed so the carb will work with a push pull like a conventional carb or barrel type.

I believe it requires something like a bellcrank :huh:

Terry

 

[sport hydro]

Yes, you need a standard bell crank attached to the rail in line with the slide. Its a tight fit, but does work. I run this setup in a SD2 b mono and have not had any trouble with response. Be sure to thread lock the carb hold down screw. It has a tendancy to back out from vibration. I run 65% fuel with 0.008" clearance. I did replace the turbo head with a standard plug head. I was burning out too many $8.00 plugs. Now I run the same plug all day.

 

[Watercadet]

This was done with angle stock off the stringer and a servo horn.

 

[Chris Thomas]

Josh I'll bring you a side exhaust to the fun run in a week. You can see it run.....

 

[tmunn]

Thanks guys i think I will try the idea watercadet has looks easy and simple..

Terry

 

[Josh Stollfuss]

Hey Chris, is that what you run in your sport 20 a OPS side exhaust?

Josh-

 

[Chris Thomas]

Yep runs pretty strong. Still searching for a good prop. The front exhaust should run even stronger than the side exhaust. I couldn't "cowl in" the front exhaust motor in this boat. I just wanted to get the thing on the water.