Sport 40 cmb hr motor

[BlueBlaster]

I have a CMB 45 HR in a phil thomas roundnose. It was a fast boat but it flip over every time going into the wind, well I was trying out ways to settle it down and I thrown it out and will only go half the course. I tried rich and fatter and it dies in the same spot. It does have a low end needle on the carb. The bearings feel good and I looked in the engine there little pitting but I don't see anything bad. This has happened to two of the same motor. Anyone use a low end on a HR or cmb. Any info would be great .

 

[glenng]

Jason, I have one of Phil's R.N. Sport 40's with a 45 Rs motor. boat is set up per Phil's instruction sheet- with one exception. I carry 18 Ounces of fuel in the nose. Make sure the rear of the strut is angled down slightly.

 

[FloridaScaleBoater]

When you say "there little pitting but I don't see anything bad" what type of pitting are you talking about? Is it in the top of the piston,,, and bottom side of the head?

If yes, I'd say the bearings have gone bad,, pieces of the balls are breaking off and causing the pitting

 

[bermudadude]

fren of mine says there are all sorts of problems with those. the cranks need to be balanced for some reason or they keep taking out bearings, but the main thing is sometimes there is metal flaking off the case behind the big bearing. this goes thru the bearing and (besides damaging it) goes thru the engine possibly causing ur pitting problem as it will also take out plugs. i dont personally own but have seen this damage . my buddy had this issue with 2 diff engines and multipole rebuilds (bearings,bearings bearings,piston/liner sets) ,,he only found out after $100 worth of fone calls.

also the p/l fit tends to just --GO. i dont know why. well i think i do after buying and inspecting a .91vac p/l but its speculation n dont wanna start a "thing" on this thread.

personally i think CMB has fallen a LOOONG way since the fathers death,they used to make a bullet proof ,reliable engine,that resold with good value

 

[David Ashcroft]

Delete

David

 

[Dasboatman]

I was unable to copy and paste John Finch's Air Age article about troubleshooting a fuel system inn this thread, but was able to copy and paste in a PM directly to Jason. This is an excellent tool and very good info contained within.

The only boater I know that has run well with CMB 45 HR is Bert Dygart . He shared his knowledge with me a while back. If I could copy and paste to Forum, I would paraphrase it for all to view.

Jason,

Let us know what the problem turned out to be

CHEERS !!! Bob

 

[Mike Betke]

Open the head volume up to .44cc and you will be much happier. That is how I got mine to run in my sport 40 and it goes pretty good. You will be very happy with your plug life.

I run the OS 40A carb on mine, but the only way I could get this motor to run consistently was to alter the head.

 

[BlueBlaster]

When you say the head do you mean the piston head or the head button? And how would you do that

 

[Mike Betke]

The head button needs to be cut on a lathe. I use a 1/4" ball nose end mill.

You can measure the cc of the head by using a syringe and alcohol.

 

[Dasboatman]

Hey Mike.

That's where Bert was running head volume also, with OS 40 A carb. I have a 45 HR in a Coyote hull I'll be playing with soon, and am going to try the OS 4E carb on that engine also.

I have a Friend that I built an SS45 for a while back with the HR in it. His was bought second hand from a boater in Australia, and Jack strapped a zoom carb onto it. Mine has the modified head volume, and my goal is to have it running when we go to test Jack's SS45 in case his engine irritates me, I'll simply drop mine into it.

What pipe, length and deck clearance are you running, Mike? Thanks, CHEERS !!! Bob

 

[Mike Betke]

Parabolic pipe, 10inches, .010 head clearance.

 

[seaducerpete]

Jason give the head to jeff schindler if he cant do it get a brass head from steve wood or alan elzer could open the head up for you

 

[Dasboatman]

Thanks, Mike

Looking forward to meeting you in Sept in Evansville. CHEERS !!! Bob