Need some advice. I fish once a week in my boat. The first time I try to start my motor (Yamaha 50 horse jet) it starts very hard, have to turn it over for a long time before it starts. Once it starts, it runs great for the rest of the day, even if it is not started for long periods of time, like a couple of hours. Does it need a tune up, spark plugs?? Don't really understand what is going on because it runs great after the first start. Thanks for any help!!

Doug

sounds funny but i had the same problem with my 135 black max merc. found out that the choke is a push button with the key. So now I prime the bulb once push and hold in the key for about 10 seconds with the start assist about 1/3 of the way open and then turn the key. It starts every time. I feel dumb for not knowing about the choke. LOL. I must have cranked that motor for fifteen mins before.

BTW its not really a choke but more of a gas bulb of some sorts, it fills with gas then when you go to crank the motor it dumps into the carb, that is why you hold it for ten seconds, so it has time to fill up.

also about spark plugs, i have heard that instead of changing them all out at the same time, you should check each on and replace as needed. saves on money. only the cold plugs are bad.

This just started to happening. It started fine for the last 3 years. On my boat, the choke is right under the key. It is like a toggle switch, you lift up on it to choke it and let it go for the choke to be off.

Doug

I'm not a mechanic.  Far from it., actually.  But it sounds to me like she isn't getting gas (i.e., the fuel is draining from the lines when you leave her sitting for extended periods).  Just a guess.

If you haven't changed the plugs in 3 years, that would be a good place to start..................Al

I'm a reasonably good backyard mechanic. I recently had that problem on my 85 horse engine. It was very hard to start first time of the day but after that, it started with a flick of the start key.

The first thing I tried was checking the timing. I reset both the Idle and highspeed timing. This made it run better but it didn't do anything for the starting problem.

After that, I adjusted the carbs as the adjustments on most carbs are an idle adjustment only. The highspeed mixture is fixed and can't be adjusted unless you change the jets. So it made sense to me that if it's getting a little too much fuel at idle, it would be hard to start. Also, my engine always smoked a lot when I first started it so that made sense to me. When I leand out the idle, it didn't smoke near as much but it was still too hard to start.

So I did what I should have done in the first place. I changed the spark plugs. That was the ticket. Starts up with just a tap of the key switch.

What I figured is that with the carbs being to rich, it coated the plugs almost fouling them but not quite.

Lean out the idle just a bit, change the plugs and that will probably take care of it.

If it doesn't, I would look into whatever type of system you have that creates your spark. You might be getting a weak spark. That would definately make it hard to start.

Thanks, I'll start with the plugs. I'll let you know.

Doug

Sounds like a fuel issue to me. I would look for simple things like cracked or cracking fuel line, or a work diaphram in your fuel pump.

Sounds like your loosing the siphon of fuel when it sits for a while.

Start simple. I don't believe plugs will cause this. If you have a bad plug either it being fouled or a cracked insulator they most likely won't work at all. However if they are old, replace them, it's good PM.

BIll

Sounds like a fuel issue to me. I would look for simple things like cracked or cracking fuel line, or a work diaphram in your fuel pump.

Sounds like your loosing the siphon of fuel when it sits for a while.

Start simple. I don't believe plugs will cause this. If you have a bad plug either it being fouled or a cracked insulator they most likely won't work at all. However if they are old, replace them, it's good PM.

BIll

I'll check those things out also. If the fuel lines were cracked, wouldn't I smell gas or see the leak? Did replace the fuel pump about 3 years ago, but maybe thats it. Will also change out the plugs. Thanks for the tips.

Doug

I'm still leaning towards old plugs. If it was a fuel issue, it would happen all the time, not just when it's cold. It could be a choke issue.  The choke isn't closing for some reason, sloppy choke linkage, etc.

If you can see down the carb throat, make sure that the choke completly closes.

Also, the plugs  do get "tired". After a period of time, the arc wears or burns away the electrode and makes the gap larger over time. The larger the gap, the harder it is for the plug to spark. Changing plugs is a cheap and easy thing to try. On an older two stroke motor, it's always a wise idea to have some spare plugs. The oil in the fuel burns much dirtier than in a 4 stroke motor and will coat the plugs in carbon. Particularly at idle.

If my engine starts running rough, hard to start, etc., I always look at the plugs first. That's usually the problem. In newer motors, that's not the case. Everything is computer controlled so this doesn't apply.

I'm not a professional mechanic so this certainly isn't written in stone but it's just been my experience on older 2 stroke outboards, the plugs are the first thing I check.

Yes it could be a cracked fuel line but that would show up more often. Even when warm. It could be lots of things. Gummed up carbs, bad reed valves, worn rings, edgy ignition system, bad fuel bulb and a mirad of other things but if the engine runs  normal other than starting, it's probably something minor. Plugs, or even an adjustment on the choke or the idle circuit on the carb.

Just my .02