Ok Guys, I hope someone can straighten me out on this, I’ve been working on a Mk 28 Merc, yea one of those automatic transmission mystery motors ! Did the usual tune up things, cleaned carb, new fuel pump diaphragm, coils checked good, new condensers, checked transmission, shifts nicely, new lube in the lower unit, good water pump ! Points set at .018. Has good spark on both cylinders !
When I try to start it I have the troll lever all the way over to the start position ! Sometimes it will fire up but sounds like it’s running on one cylinder ! The only way I can get it to run on both is if I put it in fwd and give it a little throttle ! I put it on the boat and got it running by starting it in fwd with a little throttle, opened it up and it goes like a scalded dog, slow back down and as soon as I try to go to neutral it’ll stall ! I’ve tried richening idle jet on the carb and leaning with no luck ? Started me thinking maybe the timing was messed up ?
Found the Mercury timing synchronization secquence and tried following it carefully, but it didn’t match the Mk28 even tho it said it was for it as well as the Mk10 – 15 and 200 & 250 ? What seemed to be missing in the directions was when I go to setting the advance to .275 BTDC and then advanced the mag to open the points and lock the magneto advance stop screw and nut ! There isn’t an advance stop screw & nut on this engine, nor is there a place where it should be ? The only adjustable piece on the magneto is the drag link that’s connected to the troll lever mechanism with the threaded adjustment ?
The other small detail is the reverse lock, it doesn’t work ! In the timing direction it says to screw the plastic bolt out CCW to latch the reverse lock sooner, and CW to lock it later ! But again there’s no plastic bolt screw or nut to be found to make that adjustment ????
Stumped ? Any help greatly appreciated !
Gary
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