carb jeting

[fisherman]

can any one tell me if all v-6 merc carbs are the same except the jets. are the carb throats (venturies) emulsion tubes etc. the same. my 2.0 150xr2 came with wh-44 carbs with .048 low speeds and .080 main jets. major rich. i'm wanting to lean it out a bit to get some more rpm's. just wanting to know why mine are so fat if they flow the same air as say a 2.0 150 with .056 low speeds and .064 main jets. i have access to a set of carbs off of a chrome bore 200 that has .056 low speeds and .074 and .076 main jets. i used the .056 low speeds and they cleaned up low end alot. idles much better and doesn't load up as bad. i have boyesen dual stage reeds and 32cc heads and was worried about a lean condition on the new low speed jetting snorting and burning out the reeds but so far it idles great. no wheezing and coughing. the engine is jacked up on the transom and am running a 24 pitch small hub trophy prop on a 150zx skeeter bass boat. i just can't seem to get that sreaming top end rpm. 5800 with a light load. reeds and heads helped but i want rpm,s in the 6000 range. thought leaning her out a little would help. plugs are dark chocolate color on a wide open run so i have a little room to play. hey capt'n insane"o" got any advice. your help and advice has been spot on in the past. thanks. also i disconnected the advance module and am running 22 degrees timing cranking and 92 octane super unleaded gas. any suggestions.

[Arizona Hotboater]

Carbs are different. Differing venturi sizes require differing jetting. See if you can borrow some smaller jets. If dark choclate color with 80's, drop down 2 sizes and retest. A light choclate color is perfect.
AZH.

[Edited by Arizona Hotboater on 05-23-2001 at 05:44 PM]

[Greg Moss]

Reset your timing to 26 degrees and go try it, should run better. That timing module was there to keep the timing from avancing to much when the motor was lugging. If you don't run the motor with an extreme load at mid range you should be able to run with 26 degree timing and not have any problems.

[Talon2.5]

my 2.4 i had was set at 27 degrees timing and like greg said it helped alot, as far as those 200 carbs go i would give em a try after ya do the timing.

just some thought fer ya...........later skip

[fisherman]

say talon and mr. moss. is that 26 & 27 degrees timing cranking or running the motor over 5500.

[Greg Moss]

I set mine cranking. Some say there is a big difference between cranking and 5500 but for you it will not make a difference. I really never see any change. I set mine with the plugs out on a spark checker make sure the fuel pump is off for safety.