lets try this again- need some help

[Norm Doerr]

Compare the dimensions to the old one. Also run some water through it and look for something strange.

Visually the look very close- I will mic it comparing it to the others I have and see.

Andy

See Mr. Purdue's post. Check how thick it is diameter etc. Before that, is that the same water cap that was on it before you had it modified?

 

[Andy Greene]

I have 2 and tried em both norm, same result. As soon as I can unbury my calipers I will measure the head buttons.

Andy

 

[DON MAHER]

Andy, if the motor is hot after one or two laps and the only change has been the piston & sleeve I would be looking there. Maybe free porting the ex.

Don

 

[dwilfong]

OK here goes nothing!

Dude you don't need calipers to see there is no way any thing will get in the way of the water flow.

The hole that the water comes out of and comes in are at the top of the cavity in the cap.

Pull the button out and put the cap on. you will see there is no way to block the hole. the cap will only go on so far.

I had to put shims between the cap and the head on one eng because the button was to short and the cap would not hold it down tight.

I know it can get frustrating trying to find a problem. don't chase your tail.

Step back and take a breath.

What is the ID of the stinger on the pipe?

The old eng was worn out no. Now every eng you try after that has a problem.

If you are choking a good eng it will get hot or sound rich so you lean on it to burn the fuel.

With out a 3rd channel needle you will have even a harder time if this is the problem.

You throw it in rich and it gets hot and goes lean no.

It is choked up.

CHECK THE STINGER ID it needs to be .470 or it will not run.

I know I had the same problem.

David

I know I should just keep my mouth shut.

 

[HendricX]

Problem seems clear to me .. seen it before.

Headbutton is too thin , not enough pressure on it by the cap.

Remove o-ring , screw cap on with 2 screws , and check the opening that's left for the o-ring.

Opening should be arround 0.012"(0,3mm) less as the o-ring thickness.

If the opening is smaller ... add a head-shim uppon the headbutton ,

to increase the presure by the cap to the headbutton.

What's happeing now is the cold engine is holding the headbutton ,

but if run warm , the headbutton slips out , causing fuel-mixture to flow into the cap.

Fuel and water don't mix , and will clogg ... blocking the nipples.

Also as the nipples are opposite to the bolts , restrickting the flow ,

re-drill / tap the nipples BETWEEN the bolts.

 

[Andy Greene]

Hendrick may have nailed it- and now that you mention it, I did notice fuel in the jacket when I pulled it apart the first time.

The old head button on the left- new one on the right.

Btw-

THANK YOU for everyone's input so far, its appreciated. I love this boat and for 2 years it was solid as a rock, then the handle went away- frustrating to say the least

 

[Norm Doerr]

Always look at what you changed last....it may be there.

 

[Andy Greene]

Motor,

 

[HendricX]

Glad you found it ..

Realized after posting my o-ring remarks were incorrect ,

as this GP-II engine has the o-ring sideways .. and not at the bottom as the Evo's/RS'es .

Gap is tooooooooo big for filling with headshimms.

Find someone that can machine you a ring the same size as a headshimm ,

but as thick as the difference between the two head-buttons.

I'm quite shure someone will have a CMB-GP/Evo headbutton for you ,

with stripped glowplug threads , that can be used as machining-material.

A good machinist can turn down the upper ring on the casing ,

that way the cap will 'sit' deeper , making the thinner headbutton possible.

 

[Andy Greene]

Hendrick, my thinking is, if I measure my existing head clearance and verify bowl volume- I could use the old button and shim accordingly.

Am I wrong here ?

Andy

 

[HendricX]

If you can measure the volume accurately , go for it.

But as close as I can get ... is nearly impossible.

I made a volume-gauge using a medical lab-tool called Westergren-pipette.

it divides 1cc into 200 markings.

 

[Norm Doerr]

Motor,

Yes but what on the motor? ....by the looks of the two buttons you must have changed top of piston to top of liner to,.in that one button squish drops further down into the liner than the other ???????

Not trying to cause trouble, just verifying already existing trouble

 

[jeff baham]

andy, hendrix say , to redrill the water inletand outlet so that they can be inbetween the screws ,, may the screw is swelling and they theres trash around the screw ,then when the screw cools the trash will fall out the way.

 

[Andy Greene]

Sent ya a pm Norm.

 

[Andy Greene]

I gotta ask- Jeff and Hendrix , do you guys normally move the factory positions of the jacket inlet/outlet other than vent the top for hydro use ?

These are the same ones I have run for years on this case and never had an issue, just curious .

Thanks again for the advice guys,

Andy

 

[jeff baham]

andy this is what i do on my 67cmb water jackets, is, instead of side to side water flow i move the nipple in the up downway then i leave one nipple in and that is on the back of motor(flywheelside) and on the top i drill a 1/16th hole in my water jacket for the water to flow out ,then i plug nipple on top water jacket. the 1/16th hole will restrict the water flow and will bring up motor temps.

 

[HendricX]

I always re-drill the fittings.

 

[Andy Greene]

Doesnt explain why I have been able to run it this way for years and now the issue ?

 

[jeff baham]

andy , my way , will keep the air out and not cause a bubble hot spot in top of water jacket, if i'm not mistaken andy brown does it this way (correct me if i'm wrong) most of the guys in district 5 ran or run there's this way

think about it, south to north ,water will flood everything, side to side , water will go more south then north plus with the force of running north is getting extremely hot .

motor guru's out there , please correct me if i wrong ,

 

[Don Ferrette]

I bring the water in at the 6 or 7 o'clock position when viewed from the top with flywheel facing you as this will be the hottest area. I exit the water at between the 12 and 1 o'clock positions as dictated by head bolt location. The water is under pressure so it will fill whatever voids are present regardless of where it comes in. With that being said Andy you should put the old head button back in and see if the situation changes. Looking at the pics of the two buttons I see a dramatic difference between the two in the depth into the sleeve, are you stacking a bunch of shims on the new one to get proper clearance or is the sleeve shimmed to jack up timings? Regardless the is also a big difference in overall height of the two buttons and I think there is where the problem lies in relation to the cooling jacket.