Here's what's happening, OMC gurus !

[A.J. Pastwa]

Last saturday, when the outside temp was 35 degrees, the bone stock 200 Johnrude turned a 24" Raker 5800-5900 rpms. Yesterday, after installing the heads, which gave me 115-120 cranking psi, and the slightly larger carbs, with 76D's on the top 4 and 78D's on the bottom two, the timing set at 16 degrees, and an air temp of 75, I turned about the same rpms. Since then I drilled some holes in the airbox, adjacent to each carb and haven't run it yet. Any more advice before I go back to the lake. Thanks, A.J.

[DRAGIN FLY]

115 to 120 have you closed the exhaust bleed and are you running thin gaskets. to run the same with that much temp change you are doing pretty good 5900 with a 24 about 67 ??good luck and thanks for keeping us informed

[BenKeith]

AJ

Try it with the airbox off.

It sounds like you didn't remove the baffles, just drilling a few holes in the air box won't help much. If you don't remove the baffle,or the airbox it's extremely too rich. Even with the baffle removed you will probably be too rich. I think Racer commented that with the baffles out or the air box removed, 76 and 78's mains and 106 nozzles were a safe starting point. You will have to check your plugs and pistons, since you don't have EGT sensors, and tune from there. A rich motor will not make good horsepower. Once you get your motor jetted properly with the baffles out, you will probably be running 72D's or 74D's, but you can't start off that lean or you stand a good chance off melting a piston the first five minutes of running.

When you get it jetted properly, an unrestricted air intake and with the increase in compression, you should easily gain 25 - 35 hp.

[delawarerick]

I have alwways had problems figuring out jetting. I know there are those among us that can get it preatty close but I believe in reading the plugs. The color will tell if you are at the right place. Just an opion! Rick

[dan agnew]

aj, if you are going to play with your engines and mod them you must learn to read your plugs and learn to read the pistons tops. you must buy a tool called a bore scope. snap on sells them chase down your local snap on man and spend the money. while in the truck also buy a magnafying glass with a lite so you can read the plugs you must look at the insulator under the gap. you must look deep down and you a trying to see a lite chocolate brown to paper bag in color any liter and you will kill it . spend a little save a lot


Danny

[racer]

The gutted air box does not add any power on a basically stock motor, the heads about 15 to 18 when jetted right.

[BenKeith]

I think I read AJ had installed the larger 225 carbs also. Where I missed the boat was thinking he was working on an 80's model 200 looper instead of a 96 model 200 so his air box may not have had the baffles in it to remove.

Basically, if I understand things right now, all he's done is changed carbs and heads. This should put him just a nickles worth over 225. With this being all that's done, I think he's going to have to come down a few sizes on his jets.

AJ,
If you have to go smaller on your jets and can't exchange the ones you have, I might be interested in buying those. That's about where I'm looking to start with my motor.