1978 mercury 900 starting issues (90hp outboard, tower of power.)

[terry kozmo]

Yes, update, It runs, I had to take all three carbs off and clean, replaced floats, float needles, and reasm, started hard at first. but after idle adjustments on the land, it started easy and ran good, water test next, When I think back of all the things I did to fix this problem, I realized that as old as this motor was, this is all needed to have a good running motor. It is a tricky motor to figure out, and I learned a lot, all things must work together to make it run excellent, I figure for all this work (done myself), I saved over $1000 mechanics bill. and not to mention, I saved the boating season this year. It all started with a bad coil. Recap of all I did since owning this boat I love. new alum gas tank, fuel lines, plug wires, coil, carb rebuilds, water pump impeller, rebuilt fuel pump, spark plus, adjusted timing, and now the final water test adjustments..... wow, I think I can now understand this "Tower of power"... I think I'm now good to go...

 

[terry kozmo]

well after all this , it runs great, I have a very small fuel leak when shut down, I will find it, I used nail polish to seal the small screw heads, and it may solve that issue, It is a hard initial starting motor, but once its started, it runs good, some times I have a small hesitation when I gun it, (I think that's maybe the spark advance adjustment is not correct yet), I am not sure how to get that adjustment right. (work in progress), but all in all, it runs, going to look for info on final adjustments..... Thanks to all whom helped me here.... I saved this boating season.

 

[terry kozmo]

I have it running great, but note, smelling fuel, and when shut down, note small gas spill on water, have replaced all fuel lines, and rebuilt the carbs, maybe carb pushing fuel out, float adjustment? any ideas here?

 

[Chris1956]

Run with the wrap cowling off and look for fuel drip from carb throat, fuel lines, fuel filters and fuel pump. A small amount of unburnt gas in the water is normal.