1999 Mercury 90 hp outboard

Even with a firm fuel bulb, it won't always start using the key (including last night - first time to run it in 3 weeks).

The last time I was struggling at the ramp to start the motor, a guy jumped in and started it using the advanced throttle. It started every time the rest of the day just using the key.

What did he do and how do I do it? I read some articles on my phone in the boat, but it still wouldn't start.

Is it carbed or injected? Carbed Mercs are cold natured. It use to [censored] my ex off because she could not start mine cold half the time. I would jump in and start right up. Her problem was she would forget to hit the primer. Another problem is she would no trim to at least level or a little negative. When ex was with me she always handled boat never trusted her with trailer. Almost quit trusting her loading boat when she almost put it in the back of truck once. Use of neutral button and pushing throttle forward and using primer was a must on mine.

Having to advance the throttle means you have choked it too much. Every carburated boat motor starts differently.

Carb'd Mercs are notoriously cold nature. I learns this from my old 91 115 and have done the same thing on my current and owned since new 150 xr6. Engine level while on trailer and fuel bulb tight, turn key on and press enrichment switch (mine push key switch in) count 10 seconds (1001-1010 count) press neutral button and throttle up (old 115 had a lever on the side of the control box by forward/reverse accelerator lever) and start and might have to bump enrichment switch a couple times (mine after setting up over winter), normally when used regularly don't have to bump it. Besides being cold natured they can be flooded easily. Kinda like cranking an old hot rod or old Harley. You just have to learn the touch.

Sunday night, after it wouldn't start, I went home and let it sit with motor in down position. Monday night, I took it back to the lake. I couldn't get the fuel bulb to get more than 50% firm, but on first key turn (with choke in), it started and immediately died. On second turn, it ran for 5 seconds and died. On third key turn, it started and stayed running. I ran it for an hour with no problem.

Thanks for the input, guys.

Back in the day, my Merc 225 was a bear to start until I learned to crank it and push the key in and hold it. It always cranked after I got the 'touch'. It is like cranking an old Harley.