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-   -   anyone running a Walbro 488 modded carb (https://www.rcuniverse.com/forum/speed-rc-gas-boats-236/5726389-anyone-running-walbro-488-modded-carb.html)

Shockwaver 04-16-2007 07:27 PM

anyone running a Walbro 488 modded carb
 
I have a modded Walbro 488 what is a good starting point for the low and high settings i tried low at 1 5/8 high 1 1/16 with no luck then i tried 257 settings low 2 1/2 high1 1/4 still no luck seems to be flooding? Boat wont come up runs great with 644? Your thoughts?

OLD_SLOW and in the WAY 04-17-2007 07:12 AM

RE: anyone running a Walbro 488 modded carb
 
1 1/2 to 2 on the low side and 3/4 to 1 on the high side or just start turnin it 1/8th of a turn in on each run till it clears up and the plug is toasty brown

martno1fan 04-17-2007 07:19 AM

RE: anyone running a Walbro 488 modded carb
 
are those settings not the wrong way round shouldnt it be 2 1/2 high 1 1/4low?.i have a book for settings on the 230 and 260 rc car carbs which should be similar and the factory settings say 1 3/8 high 1 1/4 low so i maybe try those and see ?.from the sounds of it the low needle is too far open id go for 1 1/4 or 1 1/8 and lean the high out a bit starting at 1 3/8 and adjust a little at a time.

wayneuk01 04-17-2007 08:09 AM

RE: anyone running a Walbro 488 modded carb
 
http://www.bonzisports.com/faq.html

Q: What are the high/low settings for my carb?

A: Stock Walbro WT-644 carb
High = 1 1/2 turns
Low = 1 1/2 turns

Stock Walbro WT-603 carb
High = 1 1/2 turns
Low = 1 5/8 turns

Walbro WT-488 big bore carb
High = 1 1/8 turns
Low = 1 1/2 turns

Walbro WT-257 big bore carb
High = 1 1/8 turns
Low = 2 turns

Walbro WT-813 big bore carb
High = 1 1/2 turns
Low = 1 1/2 turns


glennb2006 04-17-2007 08:29 AM

RE: anyone running a Walbro 488 modded carb
 
I think it's pretty clear to see that thee is not an awful lot of difference between any of the carbs standard settings, as OLD SLOW and in the WAY suggested, get it so it runs (rich) then lean off both high and low from there in small amounts until you get it running as you need it to.

Glenn

martno1fan 04-17-2007 08:45 AM

RE: anyone running a Walbro 488 modded carb
 
it seems the low needles on some of those are way high as regards turns out(open)the book i have says 1 1/8 " thats from the zenoah factory .seems you read one book you get one answer read another you get a diff answer so best thing is throw em out and do it yerself lol :D.

glennb2006 04-17-2007 07:41 PM

RE: anyone running a Walbro 488 modded carb
 
Have a look here too, some reasonable ideas to get it right.

http://www.mpbc-act.com/Tuning_Zenoah_2_Stroke_Engines

Glenn

MrMikeG 04-17-2007 08:00 PM

RE: anyone running a Walbro 488 modded carb
 
Run the low rich, it gives you more power and it is a lot safer. The load on a boat is different to the load on a buggy.
Larry is one of the best sources for engine info on here! (aka old slow.....)

Minokiller 03-15-2021 03:49 PM

488 carb on qd 25
 

Originally Posted by OLD_SLOW and in the WAY (Post 5728518)
1 1/2 to 2 on the low side and 3/4 to 1 on the high side or just start turnin it 1/8th of a turn in on each run till it clears up and the plug is toasty brown

Would this be the same on a qd 25 hi rev

Minokiller 03-15-2021 03:50 PM

From like 2003


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