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View Full Version : Mercury Tech What motor and won't idle in water



kf7strng
06-20-2011, 10:06 AM
Hi all,
I have a frankenmerc that I need some help with. I dont know for sure what it is. It is a reman block, plastic plug says 175. the heads are marked 15221 c2. Three Wh 46 carbs, black coated stator. Olive green 94 tooth flywheel, rectifier only, NO Regulator. And lastly a square pump with oil injection.

Now, on to my problem. The motor runs and idles fine on the muffs, doesn't run on the water unless started in neutral with a fully advanced throttle. I discovered that there is back pressure on the water and not on muffs which could be why it runs on muffs. It has new plugs, new impeller, a pair of new mallory 9-25100 switchboxes and a new fuel pump.

Squeezing the bulb on both muffs and water has no noticeable affect. So, I suspect timing is off. There are zero advance modules, or idle stabilizers. Can someone tell me what motor I have and the proper procedure for said motor? I know the guys here are just,as good or better than merc techs!

t.martin
06-20-2011, 10:39 AM
Look on top of the motor for the freeze plug. It should be stamped with the serial number. WH 46's came stock on 2.4 200 motors. Best carb out there IMO.

flabum1017
06-20-2011, 11:04 AM
How's the compression? Have you checked the spark on all cylinders?

kf7strng
06-20-2011, 12:02 PM
There isn't a freeze plug with a serial, as I said I believe its a reman. And builders stamp on the block says the block is a 99.

Compression is good on all 6. They all fire and appear to have good spark.

TEXAS20225
06-20-2011, 01:03 PM
a lot of motors that sound fine on the muffs wont idle when dropped in the lake low speed idle timing will have to be kicked up to keep it running its 2 minute drill