Yamaha F25ESHA intermittent push button start

02 Yamaha 25hp 4 stroke with electric push button start.

Problem began when I accidentally pulled the kill switch while running one time. It began intermittently starting via the push button, had to jump the solenoid often (no pull start). Replaced the solenoid thinking it would solve it. No dice, next the starter hung up and burned out while messing with it. Put a new starter on. Same deal. Replaced the push button starter. Same deal. Bypassed the neutral safety switch. Same deal.

Still starts immediately when the solenoid is jumped. Will occasionally try to crank or will even fire right up with the push button, sometimes ten times in a row, sometimes never.

I haven't put a multimeter to the wires yet to try to find a bad wire, but is there anything else that I should check before tracing wires or replacing all of them? I reckon it's possible the new solenoid or push button is bad (used yamaha OEM parts).

Thanks in advance for everyone's insight and thoughts.

No, the push button starter will not engage the solenoid or starter. It starts fine when you jump the solenoid. The replacement starter functions fine. By hung up, I mean the starter started the engine and did not disengage from the flywheel, which burnt it up.

If it were the kill button, it wouldn't run at all. It fires right up every time via jumping the solenoid. In fact, the kill switch is what you push to stop the motor.

It's either a bad wire or connection (have checked all the connections and all appear fine, even disconnected and reconnected to be sure), a faulty brand new push button switch(momentary button), or a component in the starting system that I'm not aware of. It's not a fuse as it does occasionally work. Sometimes when you hit the button you can hear the starter try to engage but like it's not getting enough juice or it's shorted. I really need to get a new multimeter and start checking wires, but I figured it couldn't hurt to ask here.

Start with your starter switch. Clean up all the battery conections and grounds even if they look clean. I had to pull start a 60hp one day only to find out later that my seemingly perfect battery cables on both ends needed to be sanded clean and reinstalled. That will fix clicking and no crank probleems but if the starter is staying energized I’d be looking at a bad ignition switch or I guess the solinoid could be sticking....

Voltage isn't getting from A to B when you push the starter button. Trouble shooting with a volt meter is probably your best option. Using the voltmeter push the button and see where the voltage goes to zero. Check for loose or frayed wires. Check for dirty connections. Check the fuse, maybe the fuse is bad but when it jiggles around into the right position it works for a while.

Since it works occasionally it sounds like something is dirty, loose, or frayed and when you move the boat around and get it just right it starts working again.

Yeah, that's about what I was figuring.

Was hoping someone had one of those, "Did you check this, dummy?" curealls

Might have enough daylight to mess with it a little bit this afternoon.

sunshine said:

Yeah, that's about what I was figuring.

Was hoping someone had one of those, "Did you check this, dummy?" curealls

Might have enough daylight to mess with it a little bit this afternoon.

Click to expand...

I've been through all the connections multiple times, they are all bullet connectors and appear to be in good shape. I cleaned up the starter cables with sandpaper when I installed the new solenoid and starter. Really leaning towards a faulty wire.

Will report back with success or failure in a few hours.

I have been around a slew of 25 Yamha's.

Unfortunately, most of them have been the twin carb 2 stroke models. RARELY do I get a 4 stroke in the shop. But a lot of the 4 stroke stuff is very similar, especially on the starting system.

Have seen lots and lots of neutral switches fail. Lots of them! Some of them just break off, others just quit working (internal contacts) and then there's been a few of them that have actually just come loose. One in particular, the switch was loose in it's little bracket and would start 9 times out of 10. The times it wouldn't start were the times it was in the middle of the river with a barge coming up "quickly" (6 kts?). Same motor as yours, but long shaft (F25LEHA). I wasn't the good guy on that one, mainly because I wasn't able to get it to act up at the shop--and if it won't duplicate, I can't find problem, and if I can't find problem I can't fix.

Seen a few starters fail, yes. The drive usually, not so much the motor though I've seen a starter motor or two die from being stuck engaged due to failed drive.

Seen a couple relays fail too, mostly on the earlier F25's though-as they had a separate relay. On the 08-16's they had the starter solenoid built right into the starter similar to a lot of GM vehicles of yesteryear. Those F25's (built in solenoid) have the starter "triggered" by a small wire to the solenoid. I do not remember where it's trigger comes from-I want to say from the neutral switch. If so, there's not but a couple possibilities (1) neutral switch (2) loose/bad connection somewhere. TO test connectivity, put DVOM probe on starter cable (from battery) and the other probe on the + battery terminal, at the battery itself. Now crank-or have someone crank-the engine. You don't want to see much more than 1v showing on the meter. More than 1v, you have a connection problem between starter and battery. You can do the same with the earth cable, one probe on the batt the other on the neg cable where it connects to the engine. Less than 1v is what you want to see. This is called a voltage drop test; basically tells you how much juice is lost between batt and engine. Mine (F25) had a bad battery cable connection-and it "looked" absolutely perfect. Had to cut a few inches off of the cable to get to good wire and then replaced the end. Problem solved.

I think it could still be an issue with the stop switch but that would be very rare. IIRC they'll crank over just fine with the lanyard removed, but won't actually start. That's the way my 2000 F25 was. Haven't tried it with the new one yet.

Grabbed a new multimeter on the way home. And, of course, the push button worked every time for about 10-15 minutes, so I could not replicate the problem to actually diagnose it.

This is a 2002 engine. That's what happened to my starter, it hung up on the flywheel and fried. This engine has a separate solenoid and starter. Both are new.

I did unwrap the wire bundle and go through it well, based on what I'm seeing there's a 12v+ wire into the push button, from the push button it goes to neutral safety switch (which I bypassed to eliminate as an issue), then to the solenoid. I'm going to replace that wire this weekend, put the NSS back into circuit and I have a feeling it will solve the problem.

The lanyard kill switch isn't the issue as the motor starts and runs fine when the solenoid is jumped. When the lanyard is removed it will crank but not fire.

There is really two possibilities.. either a bad starter switch or a bad solenoid.. check the solenoid for resistance on the small wires and check the starter switch for continuity when pressed.

Sent from my SM-G903W using Tapatalk

Battery connections are clean, reads 12.7v at the solenoid, same as at the battery terminals. The terminals were cleaned when I installed the new solenoid and starter. I do think I'll put replacing the battery wires on the list though.

Again, neutral safety switch is bypassed for diagnostic purposes, so it can't be part of the problem. I bypassed it by disconnecting the bullet connectors from starter button to NSS, and from NSS to solenoid and connecting them together.

Motor runs when solenoid is jumped. Not a lanyard/kill switch issue.

Starter push button lead reads 12.7v when pressed. When in normal operation, the push button lead goes to the neutral safety switch, and from there goes to solenoid. It would not function correctly with or without the NSS connected, which is why I bypassed it. I reckon it's feasible that the NSS is also bad, but I'll deal with that if it comes up once I fix it without it in the system.

Since I could not replicate the no crank situation, and considering the simplicity of the starting system now that I've cut open the wire bundles and traced everything, from what I can tell it has to be either a bad wire or a bad brand new Yamaha solenoid. When I removed the e-tape from the wire bundle, the wire was kinked and bent in a variety of ways, and messing with it resulted in the thing functioning correctly 100% of the time for probably 50 button presses. I'm thinking the small wire from the button starter/neutral switch to solenoid is bad or corroded. I know solenoids are famously problematic so I haven't ruled it out as causing intermittent issues, even though it's brand new and OEM.

It's feasible that it's a bad + wire that goes TO the push button is the bad/intermittent one as well. Without being able to replicate the no crank, I can't really find out where the voltage is or isn't though, as it reads 12.7 everywhere it should.

Connections are clean but how's the wire itself?

I misread the model...I thought it read F25SEHA, rather it's an F25ESHA. Big difference. My apologies.

I had the same motor. Positive cable was an issue. The connections were perfect. The wire itself, not so much. I cut it open and found that the conductor was nasty. That's why I had to trim some of it back. That's also why I suggested the voltage drop test. Ain't no way that thing's got 12.7x volts when you're cranking it over.

Intermittent's are a pain in the neck! Worse for techs since we don't have all the time in the world to duplicate and diagnose as time=money.

A bad or frayed wire is hard to diagnose.. I've had a few instances where voltage and resistance check out proper but unit would not work.. if you have one good strand of wire it will test properly but will not work under load.

Sent from my SM-G903W using Tapatalk

Read your voltage at your battery and see what it is showing, it should be somewhere around 13.6 fully charged. If so keep your meter on it at the outgoing side of your starter switch when you hit it if you can or recruit another set of hands. If it drops below 12 volts then you know most likely have a bad switch, battery, or poor connection if your starter is good.

Since I cut open the wire bundle and messed with it last week, every time I walk by this thing I mash the button to see if I can get it to act up again so I can put the meter on it and find where the actual problem is.

So far, no luck. It fires right over. Every. Single. Time.

I think I'm going to replace the wires to/from the solenoid in addition to the battery wires as a preventative measure/educated guess.

That or I'll take the meter with me next time I am going fishing, as you know it'll mess up as soon as I back it down the ramp while 2 or 3 other boats are waiting to put in.

Forgot to come back and update this.

It was, in fact, a bad wire going from the neutral safety switch to the solenoid.

Thanks for everyone's contributions.