Outboard engine starts quickly and then dies immediately

[rha9]

I have a 2 cycle Yamaha 8hp which is very reliable once it is running but if it has been sitting for a day or more unused it fires up on the first pull, but then dies quickly, regardless of the throttle setting.

It then doesn't even try to start on the next few pulls, but after many pulls (15-20) it does finally come to life, and runs as it should. After running for 5-10 minutes it can be shut off and restarted within several hours without any problem at all – firing up on the first or second pull and running as it should.

Any engine experts out there have any thoughts on what could be causing this behavior?

[JPA Cate]

Re gap the plugs, or replace them. If it were the idle jet, then setting up the throttle would help. Also, you could try priming the motor, with the bulb. If neither of those helps, run some carburetor cleaner through it. If that doesn't help, then find a manual on line, and strip and clean the carburetor; then make sure there are no leaks between the fuel tank and the o/b.

Ann

[sea-bee]

Here's a good summary of what to do, from an expert.

https://youtu.be/351gnO3R0Xs

[KrazyKarl]

This happened to my buddies boat we had gone for a short ride & stopped to get some refreshments. As he stood up he pulled the kill switch leash out. He put the leash back on the kill switch but for some reason it didn't reset. As we tried to start the engine, it would start but as soon as he let off the key it would die.