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Merc Carb Help needed

G

g. reed

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" can anyone tell me the diffe

" can anyone tell me the difference between carbs marked "MK36-1,2,3" and "MK39-1,2,3" they appear identical...are they interchangeable?...thanks in advance "
 
" Update...they are marked &#3

" Update...they are marked "WMK36", WMK25 and WMK39
all appear from the outside to be the same, i am wanting to put on a 115 inline 6, approx. 86 model. "
 
" G,

The carbs are pretty m


" G,

The carbs are pretty much the same, but may have different size jets and linkage arrangements.

Tony "
 
" Thanks Tony, i put a set of

" Thanks Tony, i put a set of the WMK 25's on my 115 and it would start and idle fine but a total lack of power when i got into the throttle. The original carbs were the 36 and i have cleaned and reinstalled the middle and bottom carb with the 36's and had to put a 39 on the top due to a broken fitting from the fuel enricher. I did swap the high speed jets and put the jet from the 36 into the 39. I started and ran last night on a flushette and all appears well. i did notice something that i would like your opinion on. When idling i can cover the middle and bottom carb with my hand one at a time and motor will falter and sometimes die, but when i cover the top carb there seems to be little or no effect and also adjusting the idle screw, seems to be working ok on middle and bottom carb but little or no effect on top carb...suggestions?...thanks "
 
" G,

What you are describin


" G,

What you are describing is a loss of the two upper cylinders and that isn't good. Check the spark on those two cylinders and if ok, then check the compression. You should be able to feel the engine pull against your hand as well. Hopefully, it is only the ignition and not the pistons, rings or block that is bad.

Good luck!

Kirk

P.S. Why are you changing carbs? The 86 115 is basically the 1400-1500 from the 70s rerated at the prop instead of the crankshaft. That is about all you're going to get out of that motor. I've heard of removing the midrange restriction tube and upping the jet on the middle carb .002 to help prevent detonation in #3... more info at the scream and fly forums... "
 
" Thanks Kirk...it's a lon

" Thanks Kirk...it's a long story, but basically when i was rebuilding the orig. carbs i broke the hose connector from the bottom of the bowl that goes to the fuel enricher valve, being that this fitting is pressed in and not threaded i was out of luck, so i was given this set of WMK 25's and i installed them along with a choke solenoid and just cut the fuel enricher out of the system. stated good and idled good but just lost it all when in the throttle.i am not trying to do anything other than get the motor to run. i can feel a strong suction on the top carb and when i remove my hand i get a small gush of gas out the front. compression on all cylinders ranges from 125 to 100, not the best but hopefully enough to keep me fishing for a while...i am open to all suggestions.. "
 
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