Mercury 90 2 stroke starting/running problems

[thatone123]

Just picked up a classic oil injection 90 hp 2 stroke. Plate is gone I figure it is early 90's 3 cylinder. I will be honest and say that first off I pumped a few bulbs of mix in it by accident. At first it would start for a second or 2 then die. I got crazy and did a few puffs of ether and it started. It would not keep running with the controls so I repeated and when I tried to open throttle by hand it would immediately at the slightest touch of the throttle die. Then after a few minutes I pushed the control throttle open on the controls that probably changed the timing a little and it seemed to run better and idle better. Then it would start easier and by working the throttle bar on the 3 carbs I could get it to accelerate. It would backfire some. What can I expect? Tear into the carbs? Try seafoam?

 

[oldman570]

With those motors there are several things that should be checked. Your best bet is to get a service manual that covers all the things that makes the motor run. Compression test, carb settings, linkage adjustment, timing, fuel pump test, just to name a few.With that motor you should never crank it over unless all the plug wires are grounded so not to ruin the switchbox. Lost of reading and looking at the motor is in your future, I believe.

 

[thatone123]

Yes, Did the comp test today...amazing as all tight at between 120 -125 Seems to run good now or better after some Evinrude tuner sprayed into the carbs. These seem to be a great outboard 100lb lighter than many comparable 4 strokes. I usually leave factory setting on more than one carb as it is a chore to sequence them together. Backfires if I don't push the manual throttle, but it seems to want to run under load and probably no more backfire once the backpressure of water is involved. Anymore input would be welcome.