CMB 45HR in a Sport 40

[Mike Starrett]

I wouldn't go any lower then .006" Mike.

Thanks, but I'll be raising the head to lower the compression. I will check the deck clearance before though to see what it is.

 

[Bert Dygert]

Mike,

Do you know the volume of the combustion chamber. I ran an HR in my gen. 1 Whiplash twin tanks and won district 2 last year. I've been working with an ML GP 400 all season with the HR.

All my motors have the combustion chambers opened up a bit. Stock volume was too small. Head clearance between 0.008-0.010.

Bert Dygert

 

[Samuel Hagan JR]

I wouldn't go any lower then .006" Mike.

Thanks, but I'll be raising the head to lower the compression. I will check the deck clearance before though to see what it is.

Sorry Mike I miss read what you wrote. I run .012" in my MAC.

 

[Mike Starrett]

Mike,

Do you know the volume of the combustion chamber. I ran an HR in my gen. 1 Whiplash twin tanks and won district 2 last year. I've been working with an ML GP 400 all season with the HR.

All my motors have the combustion chambers opened up a bit. Stock volume was too small. Head clearance between 0.008-0.010.

Bert Dygert

Thanks Bert. I found the head clearance was at .009. Even though you say that's good I opened it up to .017 just to see what happens. I don't have a quick way to check the head volume right now so if this helps some I'll move on to that next.

 

[Duck899]

Mike,

I had an HR in my sport 40 from Teddy. He got so frustrated with it he sold it. I also got frustrated with it and sold the motor to Eric Canto, who was also going to put it in a sport 40. The engine seemed like it would be great in a rigger, but it just didn't like the 10 lb boat it was in.

It looks like you've done everything right so far! I put a hopper tank next to the needle like you have and it helped a lot but still wasn't reliable. There may be something to that fuel draw issue someone mentioned. I never tried a smaller carb, do you have one that will fit?

Actually I have tried a carb from an RS. It has a smaller ID than the hydro carb. I even had a stuffer turned for the housing to keep the ID the same from the crank up. In the end there was little to no difference. Gotta say Jeff, I haven't seen many of these in Sport 40's and wouldn't be surprised if there is reason for it.

I will try opening up the cowl in front some to get air in. Also trying a different pipe with a large opening in the fitting and moved the fitting to the top of the pipe to try that. Also thinking of lowering the compression just a little to see what that does.

Try running it with the cowl off too

 

[Mike Starrett]

Mike,

I had an HR in my sport 40 from Teddy. He got so frustrated with it he sold it. I also got frustrated with it and sold the motor to Eric Canto, who was also going to put it in a sport 40. The engine seemed like it would be great in a rigger, but it just didn't like the 10 lb boat it was in.

It looks like you've done everything right so far! I put a hopper tank next to the needle like you have and it helped a lot but still wasn't reliable. There may be something to that fuel draw issue someone mentioned. I never tried a smaller carb, do you have one that will fit?

Actually I have tried a carb from an RS. It has a smaller ID than the hydro carb. I even had a stuffer turned for the housing to keep the ID the same from the crank up. In the end there was little to no difference. Gotta say Jeff, I haven't seen many of these in Sport 40's and wouldn't be surprised if there is reason for it.

I will try opening up the cowl in front some to get air in. Also trying a different pipe with a large opening in the fitting and moved the fitting to the top of the pipe to try that. Also thinking of lowering the compression just a little to see what that does.

Try running it with the cowl off too

Good idea, before I go cutting it up.

 

[Neil LaGarry]

I never did like the Cooper pipe. We played with the pipe length also. Got a pipe from Stu Barr ,all good.Not the black CMB pipe. The testing was done with a 45. Purple head. I am rebuilding the 45HR red head at the moment. Been having issues myself. Not with my purple heads they run all day long. My red head uses the AB pipe when running.

 

[BobGutsell]

Yes run it without the cowl. It's certainly not getting enough air, and what it IS getting is too hot because it's all getting drawn past the hot pipe. I drilled some 3/4" holes in the side of the cowl right next to the carb on mine and made a huge difference. You can tidy up the holes by gluing bolting on some scoops.one forward and one rear facing so you're getting fresh air drawn through there. Make the holes very slightly behind the carb so in the unlikley cahnce of water ingress, it splashes onto not into the carb.

It's also not the torquiest engine you'll ever come across, My one prefers to like to rev on smaller props.

 

[Mike Starrett]

I never did like the Cooper pipe. We played with the pipe length also. Got a pipe from Stu Barr ,all good.Not the black CMB pipe. The testing was done with a 45. Purple head. I am rebuilding the 45HR red head at the moment. Been having issues myself. Not with my purple heads they run all day long. My red head uses the AB pipe when running.

I normally ran this engine on a CMB pipe that I got new when I bought the engine. The Cooper pipe was an "Oh WTH, Let's try this and see what happens." Not much happened. I've also had a couple purple heads and liked them both.

 

[Mike Starrett]

Yes run it without the cowl. It's certainly not getting enough air, and what it IS getting is too hot because it's all getting drawn past the hot pipe. I drilled some 3/4" holes in the side of the cowl right next to the carb on mine and made a huge difference. You can tidy up the holes by gluing bolting on some scoops.one forward and one rear facing so you're getting fresh air drawn through there. Make the holes very slightly behind the carb so in the unlikley cahnce of water ingress, it splashes onto not into the carb.

It's also not the torquiest engine you'll ever come across, My one prefers to like to rev on smaller props.

I was also beginning to think pulling air around that pipe might be a problem. Thanks for that advice. Mike

 

[anthony_marquart]

I have a AA45 that I'm yet to run,.. (hard to believe) It's not new but in fantastic shape. Seems to have been prepped by someone. I checked last night and the clearance was 0.0085,.. checked multiple times,.. same number.. Do you guys think this might be too tight?

 

[Samuel Hagan JR]

I have a AA45 that I'm yet to run,.. (hard to believe) It's not new but in fantastic shape. Seems to have been prepped by someone. I checked last night and the clearance was 0.0085,.. checked multiple times,.. same number.. Do you guys think this might be too tight?

Anthony I was told by Al to break in the A/A at .012" Then tighten down to .008"

 

[Mike Starrett]

I have a AA45 that I'm yet to run,.. (hard to believe) It's not new but in fantastic shape. Seems to have been prepped by someone. I checked last night and the clearance was 0.0085,.. checked multiple times,.. same number.. Do you guys think this might be too tight?

Anthony I was told by Al to break in the A/A at .012" Then tighten down to .008"

This thread is not about AA engines Thank You

 

[Samuel Hagan JR]

When's the next time your going out to the pond Mike. I'll try and ride out there. I'll bring some stuff with me.

 

[Mike Starrett]

Probably Sunday

 

[Dasboatman]

Hey Mike,

Here are a couple examples of how I get fresh air to Sport 40 carbs. Openings are 3/8" X 1 1/8". You don't need a scoop, these flush versions will draw all the air you need, and let most of the water blow pass.

The only successful CMB 45 HR in a Sport 40 hull I know of is Bert Dygart's. He has given you his set up in this thread, it works - I would start there.

Has anyone compared the intake timing of the HR to an RS??

I have a good Friend that tried to get an HR in a SS45 running. He saw the same problems you have, and went to the smallest bore ID CMB carb he had. He even adapted an OS 40 A carb to his own engine later without much success. To condense the story - the HR in the SS45 was replaced with a CMB 45 RS, and his CMB 45 HR is now here at my house, but in an outrigger which I have yet to run. CHEERS !!! Bob

 

[Mike Starrett]

Hey Mike,

Here are a couple examples of how I get fresh air to Sport 40 carbs. Openings are 3/8" X 1 1/8". You don't need a scoop, these flush versions will draw all the air you need, and let most of the water blow pass.

The only successful CMB 45 HR in a Sport 40 hull I know of is Bert Dygart's. He has given you his set up in this thread, it works - I would start there.

Has anyone compared the intake timing of the HR to an RS??

I have a good Friend that tried to get an HR in a SS45 running. He saw the same problems you have, and went to the smallest bore ID CMB carb he had. He even adapted an OS 40 A carb to his own engine later without much success. To condense the story - the HR in the SS45 was replaced with a CMB 45 RS, and his CMB 45 HR is now here at my house, but in an outrigger which I have yet to run. CHEERS !!! Bob

Yep, I agree Bob. Thanks, Mike

 

[Randy Cartright]

Mike when you get mad enough I might buy it.

Randy

 

[anthony_marquart]

Wow,.. it did have some content on .45 deck height.. so I asked a question.. maybe you should make private thread..

I have a AA45 that I'm yet to run,.. (hard to believe) It's not new but in fantastic shape. Seems to have been prepped by someone. I checked last night and the clearance was 0.0085,.. checked multiple times,.. same number.. Do you guys think this might be too tight?

Anthony I was told by Al to break in the A/A at .012" Then tighten down to .008"

This thread is not about AA engines Thank You

 

[chris thornton]

Mike i put in an HR in my 40 (its one of berts engines) for the wine run and it runs fine still not as fast as i would like but it does run good. it is still the same setup as when you had it , i havent changed anything except put in a new motor. if that helps any. i did shorten the pipe by 1/2 in. though.