View Full Version : Mercury Tech lean sneeze?
P man
10-06-2008, 06:56 PM
This motor Ive got runs great once up on plane but the thing wont idle worth a turd. It appears to be lean sneezing. If i play with the enrichener constantly i can sort of smooth it out but if I just let it run, it will die. Also, the hole shot sux... I have to press the key just before I step on it to get it to come up.
Now... The motor is an early 80's 2.4 200 (finger ported) with WH20 carbs. Ive got .046 idle jets in it. I tried pulling them out today and the motor idles the same without them. I also played with the timing arm and couldnt really find a smoother spot.
Ive had these carbs apart and cleaned more time then I can count... any ideas as to what else this could be???
what about a bad gasket on top of the carbs?
any ideas on what else I can test for???
fatjohnson73
10-06-2008, 07:46 PM
is it sneezing out the carb throat? if so check yer reeds.
xr1million
10-06-2008, 08:12 PM
I dont know these carbs by heart but the lows speed jet wont affect idle (at least very much, only saying that to save myself), they dont create a restriction until a slight amount of throttle is applied. These carbs have air/fuel mixture screws right??? Its not an EPA motor so they should be sticking out in the open. Have you played with them?
Also like fatty said, check the reeds. But only after playing with the mixture screws and if they dont help!
Jay Smith
10-06-2008, 08:14 PM
Could be reeds , could be idle jets OR could be idle timing too high...
just a thought,
James Harvell
10-06-2008, 09:08 PM
could be a weak stator,check resistance ,hope this helps
Riverman
10-06-2008, 10:53 PM
P man, you may want to PM Scott in MN, he has a hot carb motor and fools around with jets a lot. He will let you know if you are close with the idle sizes.
P man
10-06-2008, 11:25 PM
the WH20's dont have mixture screws.
... In the daylight I cant see anything coming through the throat but the motor will sneeze and shake, dropping the rpm's each time.
Ill check the stator... never thought of that.
Could be reeds , could be idle jets OR could be idle timing too high...
just a thought,
Thats exactly where I would look first.
T-REX
10-07-2008, 08:00 AM
Are these "Cherry" carbs????....I have a set ov 20's that I have never got to quit sneeze'in, and kum to find out they have been molested!!:eek:....Once sumbody jacks wit tha progression holes and does them "Super mods", U kan throw them away, unless U run them on a fix'd time'n mota wit plenty fuel, and idle rpm @ 1500up!!....
Make sure ya plugs are good, Had a 2.4 pop so bad it would almost die, found out tha plugs wuz my culprit(and they wuz not that old)....
I have .052 jets in my brothers 2.4 chrome bore(200hp), .076's in tha mains, Idle time'in iz 8* BTDC.......summertime....runs good, will sneeze once in a great while.........Winter will sneeze more offen, even if the idle jets are dropp'd to .048.....we go to .080's in winter on tha mains......
And, sumtimes ya never git a carb to work rite(I have sum ov those too)....I didn't say a set ov carbs, I said A carb....It only takes one to ruin ya day!!!
P man
10-07-2008, 11:55 AM
Also I forgot to mention this is a 2.4 powerhead mounted on a 2.5 mid.... would it make much of a difference having the bigger exhaust ports in the adaptor ?
4JawChuck
10-07-2008, 05:08 PM
I had a similar problem with my 90 Merc, found the carbs were not sync'ed properly and the center carb was open a few thousandths at idle causing the lean sneeze. Also your idle mixture may need adjustment, they should all be the same amount of turns out.
T-REX
10-08-2008, 07:56 AM
Also I forgot to mention this is a 2.4 powerhead mounted on a 2.5 mid..
Don't matter.....They are the same size outlets:thumbsup:
M.CHAPMAN
10-08-2008, 04:38 PM
When you went through the carbs did you check and make sure the idle tubes that run fron the top of the carb down through the throttle bore were clear? I run a torch tip cleaner through them and hold them up to a light and make sure they are clear of varnish, trash, etc. If the are partially stopped up this will lean out the idle circuit. Just a suggestion.
-Michael
id check to make sure they are sync'ed .... even if it looks good id still go through and snap every one...... and watch when ya tighten the set it can walk.... AND WILL SOMEONE PLEASE TELL ME WHERE THE AIR/IDOL MIXTURE SCREW IS ON A WH 20... CUZ I STILL CANT FIND IT...
M.CHAPMAN
10-09-2008, 07:54 AM
There are no mixture screws on WH carbs, only idle air jets that meter air introduced into the idle circuit. (behind the 7/16 brass hex plug at the top). The larger the air jet the leaner the mixture, the smaller the jet the richer.
P man
10-09-2008, 10:27 PM
.. hahahaha ok I think I may be on to something here (this may get some of you laughing)
The idle jet is behind the hex plug on the sides eh????
Well apparently (if that is the case and from what Ive looked up it sure as hell is) then whoever put these together was clueless... theres nothing in there!!!!!
Those .046 jets I told you guys about were screwed in the front i.e. the front vent holes.
Thats why I thought the idle jets were in the front of the wh20's
From what Ive looked up, my motor is not supposed to have any jets in the front and .046 idle jets... in their respected spots.
...WOW
It sounds like you figured it out :D
P man
10-09-2008, 10:36 PM
hahaha
Thank you for teh help... its much appreciated
T-REX
10-10-2008, 07:16 AM
Yup, anuther set ov MOLESTED carbz......WH carbs are tha simplist ov all tha merc carbs, and U would be supriz'd how many sets git's screw'd up and sent down tha road az a good set........Sum guyz are afraid to ask for help, and sum juss ain't got a clue, and when ya buy them "Cherry" carbs from one ov thoze, U wind up wit grey hair and a ulser.......I knew U could figger it out once ya asx'd enuff questionz.........
When in doubt, enuff questions will figger it out!!:cheers:
M.CHAPMAN
10-10-2008, 07:28 AM
Good to hear you figured it out, sometimes it's a simple thing. Bet ya cured it's cold now...........
j_martin
10-10-2008, 09:38 AM
.. hahahaha ok I think I may be on to something here (this may get some of you laughing)
The idle jet is behind the hex plug on the sides eh????
Well apparently (if that is the case and from what Ive looked up it sure as hell is) then whoever put these together was clueless... theres nothing in there!!!!!
Those .046 jets I told you guys about were screwed in the front i.e. the front vent holes.
Thats why I thought the idle jets were in the front of the wh20's
From what Ive looked up, my motor is not supposed to have any jets in the front and .046 idle jets... in their respected spots.
...WOW
You know, if you slide down the page and read the descriptions in the parts list, it'll tell you which is which.
I read the comics with my kid. He reads the pictures and I look at the words.
Yer right, I needed a laugh.
John
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