Mercury 150 V6 blackmax idles only with one bank, 3 cylinders

[eddy50]

I have a Merc 150 v& XR2 from around 1985. Runs well in higher rpms anf full throttle but idles and starts with only 3 cylinders, one side. And I also noticed when it was run without flame arrestor that there is a small hose that comes to the lower edge of flame arrestor frame. When I have higher rpms, everything is fine but when it drops to idle (about 800 rpm) that hose start to spray gasoline. I can use it but would like to get it running as it should. Anu ideas what to do ?
Carbs are WH-29 and just put new needles and they sem to work ok.

Thanks

Esa

 

[Dukedog]

have ya got tha manual (oem)? do you know how to test electrics ie: stator, trigger? that "hose" should come from a bib on tha bottom of tha reed plate and plug on to a bib on tha bottom of tha air box...very small amount of fuel there at idle is normal...more like a mist... not a steady "stream".

 

[Chris1956]

I am not sure of the year of the service manual I have, but the troubleshooting is pretty common across the years. According to the service manual, you could have a bad idle stabilizer or a bad low speed winding on the stator. You could ohm out the stator leads.

The test for the 40A stator coils are. You may have the older 16A stator:
Blue and red leads should have 3500-4200 ohms
Blue/white and red/white should be the same.
red stator lead and black stator lead should be 90-140 ohms
red/white stator lead and black stator lead should be 90-140 ohms

Swapping stator leads will cause the no spark to move to the other bank of cylinders, if the stator is bad. Also, see if you have a shift interrupt switch. If it sticks, it kills spark to 1/2 the motor.

There are tests for the triggers, however, they would affect spark to pairs of cylinders, not 3 cylinders.

 

[Dukedog]

his will be a 16 ..don't remember what ohm readings are for tha it though....no shift deal,,

 

[eddy50]

Thanks guys, I will try to check those and I don't have the service manual. And about the fuel spray, yes it is nothing or more like a mist when I have higher rpm but when I drop it to idle (and the only 3 cylinder burn) it is more like a steady stream. I thought that it is because of the crbs feed all the time but when the cyls are not burning the unused gas is flushed out.

 

[Dukedog]

fuel spray gets bigger 'cause ya have cylinders that arn't firin' at all....

16 amp stator

Blue Blue/White Red Red/White

Engine GND Engine GND Engine GND Engine GND

5000-7000 5000-7000 90-200 90-200

trigger

Wire (yellow sleeve)	Read To (black sleeve)	Resistance
Purple wire(#1) White wire(#3) Brown wire(#5)	Brown wire(#2) Purple wire(#4) White wire(#6)	Purple wire(#1) White wire(#3) Brown wire(#5)	800-1400 800-1400 800-1400