So I got a 2010 50 hp Yamaha 2 stroke that I've had about a month. I don't think the Prime Start feature on it is working. I can put it into the emergency start mode and it will crank right up, but it's really difficult to start it without doing that.

It is supposed to be activated by pushing in the key switch, but I can't tell that anything happens when I do that. I've read that I should hear the solenoid click when I push in the key, but I can't hear it and I got my wife to listen and she doesn't hear anything either. So before I start taking it apart I thought I would ask here - is there supposed to be an audible click?

I sure wish they could have put a manual choke on it. Thanks for any help.

No audible click is supposed to be heard Mr. Steve. Those work by wax balls that heat up inside the prime start solenoids. I can’t remember which wire it is that you’ll need to check power on, but I’m thinking it’s the blue wire. I’ll have to check the service manual tomorrow. Send me a pm tomorrow before 5 pm and remind me.

Also those are very common for the timing to be off. Lots of folks jack with the potentiometer that controls timing on the side of the Cdi unit. Because it’s out in the open, folks can’t help themselves from messing with it. 8° + or - 1° ATDC is idle timing spec. Idle mixture pre set screws are 1.5 rounds out.

If either one of those is out of spec, it’ll be hard to crank BUT will run like crap at idle too normally unless you have an oddball engine that needs altered timing or idle mixture which I doubt.

Thanks Hevishot, I had read conflicting info regarding the click. Once it starts, it runs great for the rest of the day, so that makes me think it's the Prime Start. And if I spray the smallest possible amount of carburetor cleaner into it that will fire it right up too. It may be something beyond my skill level.

Ok, so measure resistance between the blue and black wires of the prime start solenoids. At normal room temp, you should read between 2.32-3.48 ohms.

Remove the solenoids and connect 12 volt positive to the blue wire on the solenoid, and ground to the black wire while sitting on a work bench. Wait several minutes and check to see if the piston height of the solenoid has moved quite a bit. If not, replace the solenoid. If it does move, that means that you don’t have 12 volts on the blue wire when you press the key switch in. You’ll have to figure out why.

Thanks for the info, Hevishot. I watched a video of a guy doing most of that, but he noted that Yamaha said that the solenoids hardly ever fail. I'm thinking the issue is with the key switch and it's not sending any power.

They don’t fail much, but I have seen them fail a few times. Typically the odds of failure is higher if the engine has sat up for a length of time and varnish has built up on the solenoids.

Thanks again. I measured the resistance at 3.0, but then switched the meter to voltage and got my wife to turn the key to on and then push it in. Voltage remained 0.0 throughout that, and I thought that there should be voltage at the solenoid if it's working. Is that correct?

When she cranked it the voltage showed 2.2, which didn't make any sense to me, but there is always a lot I don't understand on an outboard. Whatever it is, it will be the strangest and most unusual thing that has ever happened; that's always my luck with a motor.

I bought it from a used car salesman, and of course it fired right up when he showed it to me. He knew I was coming, and I'm sure he had already cranked it before I got there. It runs great once it cranks when cold, so it's gotta be something in the Prime Start.

I'm trying to test it without removing it. I have found that once I take something like that apart, that's gonna be the end of it. A man has to know his limitations. . I will pull the solenoid out only a last resort. From what I've read, there should be 12 volts going to it when engaged. If I run a jumper wire from the battery + to the blue positive of the solenoid, leave it there for 15 seconds or so, then crank it, that should mimic the way it's supposed to work and it should crank if the plunger is moving and the rest of the system works. Or is that a bad idea?

Yes that will work for testing. I’ll bet you a turkey hunt that it’s either one of two things; the choke engagement wire is either disconnected from the key or its broken, or, the key switch is bad.

Easy to check. If you can’t figure it out, get it to me and i will fix it for you.

Many thanks for the offer, and I may take you up on it. I gotta take half the boat apart to get to the key switch, but that might be something I can do. If it will crank with the jumper wire on I might just run a couple of wires to the front and put a toggle switch in the control center. I've always thought the push in key switch was a bad idea. Hey, we can do the turkey hunt either way.

Hope you get it going PCP. All this, test this wire / test this wire, stuff has me plum confused

Well if need be, let me know. I can meet you in Guntersville to cut down the distance for you by quite a bit, like near top of the river at one of the boat ramps.

I’ve got the same motor. Sucker is cold natured, but once you get it warmed up it runs strong. I had an old man who’s a retired marine mechanic tune it up this summer. It’s running better right now than it ever has.

It will push my 17.5 ‘ boat 32 mph and barely uses any gas.

So I jumped a wire from the battery + to the + of the Prime Start solenoid, giving me 12 volts to the solenoid and mimicking what is supposed to happen when you press in the key switch. Unfortunately, it didn't crank. I had hopes that was gonna crank it. I flipped it to the emergency start mode and it fired right up.

I didn't think I could get the solenoid off without removing the oil reservoir, but I was able to get a long screwdriver to it and the screw wasn't even tight. I am not the first to try to fix the thing, and a previous owner must have tried and given up. Sure looks like the car salesman pulled a good one on me by cranking it with starting fluid before I got there.

I tested the solenoid with it out of the motor and the piston moves the way it is supposed to do, so I guess there is a problem with the pump or the wax diaphragm inside the Prime Start. But since the motor doesn't send any power to it, the key switch must also be bad. I believe this motor has set up a lot, and that's always bad for one.

Hevishot, does the fact that it cranks in emergency start mode tell me anything about the Prime Start, or does it just bypass the whole system when in that mode? I'm thinking it just bypasses it and there is something wrong inside of it. I've read on other forums of folks just running it in emergency mode all the time, but that seems like a bad idea to me. I can use it by removing the cowling and giving it a tiny shot of carburetor cleaner just before putting the boat in the water, but it will eventually have to be fixed. Thanks again for the help

So walk me through the process of how it does crank. Are you pulling the fast idle lever up?

I can do better than that, it cranks!

Before I put the solenoid back in yesterday, I put as much carburetor cleaner into the Prime Start as I could get. I used a piece of plastic to push down the valve that is controlled by the Prime Start solenoid, and kept doing it until it wouldn't hold any more. Then I turned the motor over a few times to try to get the cleaner inside the system, and let it sit overnight.

I just now walked back out there to test it. I had figured out that the solenoid heats up about 10 degrees when power is applied to it, so I used the laser and the temp was 95, which is the current air temp. Then I turned on the key and held it in for 30 seconds. I measured the temp again and it had not changed. That part of it just doesn't work. I can't see a wire that is off, so it must be an issue inside the switch.

So then I ran the jumper wire from the battery + to the solenoid + and left it there for 30 seconds. I checked the temp and it was 104, and I knew that should have caused the piston to move. So I cranked it and it fired up instantly! I guess the carburetor cleaner opened it up.

So now I can drop several hundred on a new switch, or find a more "thrifty" way. I'm thinking I would rather take that blue wire loose, then hook a wire to it and run it to the area right beside the key switch. Then install a push-pull type switch that actually looks like an old style choke. When I try to cold crank it, pull the switch out and leave it on until the motor is running smoothly, then push it in to disconnect the system.

I'm sure this would work, but my only concern is that if someone forgot to push it back in that might cause the solenoid to eventually overheat. What do you think? If it could be dangerous, I at least need some type of switch that would have to be held down to work.

Is that switch repairable? It won't be easy to get to it and get it out, but I guess I should try that unless it is sealed up. I can't tell as it is.

Is the switch in the control box, or on the dash?

It's a stick steering boat; the motor controls are on the right side. I really don't like where they put it; it's down really low. I can take off the access cover and pull the switch out just a little, but I've probably got to take a lot of the boat apart to get it out and replace it. That's a job I think I could do, but I'm not sure which switch I would need. I followed a Yamaha link and the switch it led me to was $259 + shipping. But then I found a generic switch that was only $50.

I would just change the switch if the $50 will work.

That’s what I was going to suggest, aftermarket switch. That’s what I would do

PCP, I have the complete Yamaha control that fits that motor sitting on a boat right now. Tell me what’s a fair price and it’s yours.

There ya go Mr Steve ^^^