Irwin Outboard Quiet Pipe length

[J_Moore]

Can someone give me a good starting point to put my o/b pipe length at measuring from the glow plug on through. thanks

 

[james irwin]

Can someone give me a good starting point to put my o/b pipe length at measuring from the glow plug on through. thanks

IF YOU WILL ALLOW ME , I WILL TRY

TOTAL WEIGHT OF BOAT ?

PROP

WHAT KIND OF BOAT ?

HOW DEEP IS THE ENGINE ? ?

 

[J_Moore]

Can someone give me a good starting point to put my o/b pipe length at measuring from the glow plug on through. thanks

IF YOU WILL ALLOW ME , I WILL TRY

TOTAL WEIGHT OF BOAT ?

PROP

WHAT KIND OF BOAT ?

HOW DEEP IS THE ENGINE ? ?

Weight of boat not sure.

Prop- M440

Boat TS2

Prop is 1/8 inch to centre of prop below the running surface

Lower unit lawless

Power suppy MAC

 

[topfuel443]

sounds really deep to me, especially for the MAC, I usually run my mod boats baout 1/8 above (sometimes more) the ride surface. The MAC likes lots of RPM, you will have a hard time getting that with the engine as deep as you say. hope that helps, ~James.

PS, For the quiet pipe length, I usually leave a small gap between the header and pipe, about 1/8 should do, thatll get you very close with the length.

 

[J_Moore]

sounds really deep to me, especially for the MAC, I usually run my mod boats baout 1/8 above (sometimes more) the ride surface. The MAC likes lots of RPM, you will have a hard time getting that with the engine as deep as you say. hope that helps, ~James.

PS, For the quiet pipe length, I usually leave a small gap between the header and pipe, about 1/8 should do, thatll get you very close with the length.

Sorry meant above the running service. So what is the pipe length measureing from the plug to the weld. THanks

Jeff

 

[Jerry Wyss]

I run mine @ 8 3/4's inches, the Mac O/B has a perdy high exhaust port timing.

It is a very high performance engine and has critical temperature and fuel demands

to make it run right. You will have to move the length to find what suits but thats a

good start point.

JW

 

[J_Moore]

I run mine @ 8 3/4's inches, the Mac O/B has a perdy high exhaust port timing.

It is a very high performance engine and has critical temperature and fuel demands

to make it run right. You will have to move the length to find what suits but thats a

good start point.

JW

Thank you very much Jerry.

This was the third time i asked about a ball park length with no reply till now. Even Mr Irwin would ask some questions on my set up but never any reply at all all three times. Makes ya wonder sometimes. Thanks again Jerry for taking the time.

Jeff

 

[james irwin]

I run mine @ 8 3/4's inches, the Mac O/B has a perdy high exhaust port timing.

It is a very high performance engine and has critical temperature and fuel demands

to make it run right. You will have to move the length to find what suits but thats a

good start point.

JW

Thank you very much Jerry.

This was the third time i asked about a ball park length with no reply till now. Even Mr Irwin would ask some questions on my set up but never any reply at all all three times. Makes ya wonder sometimes. Thanks again Jerry for taking the time.

Jef

HEY JERRY , SORRY ABOUT BEING SO DADGUME SLOW . 8,5 IS A GOOD STARTING POINT . YOU WILL PROBLLY END UP ABOUT 8 O 8.250 I JUST DID FINISH A ROUND WITH THE FLUE .. SEE YA , LOL

 

[J_Moore]

I run mine @ 8 3/4's inches, the Mac O/B has a perdy high exhaust port timing.

It is a very high performance engine and has critical temperature and fuel demands

to make it run right. You will have to move the length to find what suits but thats a

good start point.

JW

Thank you very much Jerry.

This was the third time i asked about a ball park length with no reply till now. Even Mr Irwin would ask some questions on my set up but never any reply at all all three times. Makes ya wonder sometimes. Thanks again Jerry for taking the time.

Jef

HEY JERRY , SORRY ABOUT BEING SO DADGUME SLOW . 8,5 IS A GOOD STARTING POINT . YOU WILL PROBLLY END UP ABOUT 8 O 8.250 I JUST DID FINISH A ROUND WITH THE FLUE .. SEE YA , LOL

Thank you very much for your reply Mr. Irwin. Sorry to hear about the flu.

Thanks

JEFF

 

[david cox]

Hi Jeff:

I would suggest a pipe length of about 2". Then lean in your needle all the way till it closes, and then open it by about 1/4 turn. Don't cool the engine with water, it works best to be cooled by air. Oh and one other trick, put some fine sand in your carb, as it will help to break in your engine and "hone" the piston and sleeve fit.

Good luck and let me know how everything works out.

 

[J_Moore]

Hi Jeff:

I would suggest a pipe length of about 2". Then lean in your needle all the way till it closes, and then open it by about 1/4 turn. Don't cool the engine with water, it works best to be cooled by air. Oh and one other trick, put some fine sand in your carb, as it will help to break in your engine and "hone" the piston and sleeve fit.

Good luck and let me know how everything works out.

Geez thanks for your help Mr. Harry Cox. Maybe i should put a stone in my sleeve so as it hits my head it will give that little extra mushroom effect to tighten up my compression ratio on the top end. Who needs the sleeve squeezers when you have stones huh. I tryed your suggestion of 2 " on the pipe length but i found that i maxed out on the rpm band and now i have to back it down so that others aren't jelouse of my record setting speeds. If you drive a nail throught the case it will relieve the case of to much extra crank case pressure as to not flood the engine with all that unnessary fuel that just goes out the pipe anyway as the cold plug i run can't burn it anyway.

 

[david cox]

Jeff I like your idea of driving a nail through the case, but I still think you need to shorten the pipe to 1.5". You might find that this extra RPM won't turn your prop so I would suggest removing one of the blades completely. Sounds like your piston is still a little sloppy, so take out the sleeve and drive over it with your truck. The oval shaped sleeve will now give you the perfect piston fit you have been looking for.

David

 

[J_Moore]

Jeff I like your idea of driving a nail through the case, but I still think you need to shorten the pipe to 1.5". You might find that this extra RPM won't turn your prop so I would suggest removing one of the blades completely. Sounds like your piston is still a little sloppy, so take out the sleeve and drive over it with your truck. The oval shaped sleeve will now give you the perfect piston fit you have been looking for.

David

Thanks Again Mr. Cox. My truck didn't seem to fix my problem so i smashed the sleeve a little with a smooth rock and now i hope i have that oval effect you where talkng about. I can send pics if you want. I sent out my prop for the removal of that blade and the guys sayed i was nuts until i explained your theory to him and he agreed but when i picked it up he had this funny smerkish laugh to his face. Found out later he just had gas. I filled in the nail hole with with JB weld as i found that it screemed like your cousin cuz it was lean for some reason. Seems to be knocking abit. Gunna put that hair spray canister on her and see if she just needs a bit more volume to the pipe. Thanks agian for your help good buddy.

 

[Propualsion]

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