ops .67 engine shim

[feallun]

Hi,

I have ops .67 and I burn some plug.

I engines is not to lean.

What is a size for the shim?

I use redMax 50%.

Thanks for your help.

feallun

 

[Ed Knudsen]

Hi,
I have ops .67 and I burn some plug.

I engines is not to lean.

What is a size for the shim?

I use redMax 50%.

Thanks for your help.

feallun

Feallun;

I've run a lot of OPS .67's over the years. I usually set the head clearence at .012 running 45%-55%. There are Lot of causes for burning plugs. Couple of things to check. Make sure your bearings are okay and also check the rotor. If it's a disc style I have had the disc pin start to go bad allowing the rotor to wobble, blowing plugs and then of course it eventually breaks. Common failure in a OPS .67. One reason why they eventually changed to a drum rotor.

Ed

 

[Norm Doerr]

Hi,
I have ops .67 and I burn some plug.

I engines is not to lean.

What is a size for the shim?

I use redMax 50%.

Thanks for your help.

feallun

Feallun;

I've run a lot of OPS .67's over the years. I usually set the head clearence at .012 running 45%-55%. There are Lot of causes for burning plugs. Couple of things to check. Make sure your bearings are okay and also check the rotor. If it's a disc style I have had the disc pin start to go bad allowing the rotor to wobble, blowing plugs and then of course it eventually breaks. Common failure in a OPS .67. One reason why they eventually changed to a drum rotor.

Ed

Yup it sounds like it is time for a rebuild.. Be sure to lap the rotor and backplate so they seal AND replace the pin and maybe the rotor.....if you don't ..welllll.. BOOOM! There are some good papers on rcboat.com IR replacing bearings and lapping the rotor.

 

[feallun]

I have a drum motor.

And yes, I have a broken gasket.

 

[Bigbird]

I have a drum motor.And yes, I have a broken gasket.

What kind of plugs are you using?

BB

 

[feallun]

I have a drum motor.And yes, I have a broken gasket.

What kind of plugs are you using?

BB

I use a mc-9

 

[feallun]

Feallun;I've run a lot of OPS .67's over the years. I usually set the head clearence at .012 running 45%-55%. There are Lot of causes for burning plugs. Couple of things to check. Make sure your bearings are okay and also check the rotor. If it's a disc style I have had the disc pin start to go bad allowing the rotor to wobble, blowing plugs and then of course it eventually breaks. Common failure in a OPS .67. One reason why they eventually changed to a drum rotor.

Ed

When you write 0.012 did you tell in imperal or metric system??

 

[Bigbird]

I have a drum motor.And yes, I have a broken gasket.

What kind of plugs are you using?

BB

I use a mc-9

OPS is all I have ever run. I have found that Redmax is not the best fuel for the 67. I have also found not to go over 40%nitro. I have always gotten better reliability with 40% (when my boat stays right side up)lol

BB

 

[PakMan]

Feallun;I've run a lot of OPS .67's over the years. I usually set the head clearence at .012 running 45%-55%. There are Lot of causes for burning plugs. Couple of things to check. Make sure your bearings are okay and also check the rotor. If it's a disc style I have had the disc pin start to go bad allowing the rotor to wobble, blowing plugs and then of course it eventually breaks. Common failure in a OPS .67. One reason why they eventually changed to a drum rotor.

Ed

When you write 0.012 did you tell in imperal or metric system??

To answer your question: 0.012-0.016" head clearance is fine for a scale boat. That is inches. Or approx. 0.355 mm

Also, 50% RedMax Marine mix will work fine in that motor. Check the exhaust timing. For a 14-16 pound scale boat it should be about 177-178 Degrees.

PM me if you need any more help.

David Jensen