Engine won’t start when hot

[Beachbummer]

Do you have the mechanical controls? You can push the button on the center of the lever to accelerate in neutral. It should crank then.

 

[FLJetBoater]

Do you have the mechanical controls? You can push the button on the center of the lever to accelerate in neutral. It should crank then.

No, it's an E-series...2020 242SE

 

[Neutron]

Its an E series correct? so no cables all eletronic

 

[Neutron]

Makes it hard when there isn't any codes to set you in a direction.
If you have a multimeter check the resistance on the pickup coil at the plug. If you look down the rear of the engine, there is 5 wires coming out three are green and go to a round connector those are for charging. The other 2 wired one black and one white go to a flat connector. Unplug it and test the ohms value on the side that goes to the engine. This is what gives you spark timing. It should be between 450 and 560 ohms. Heat could be affecting it. Check cold then check when it wont start.
If its high, it will kill spark

 

[Neutron]

Have you verified if its losing spark of fuel?

 

[FLJetBoater]

Its an E series correct? so no cables all eletronic

correct

 

[FLJetBoater]

Have you verified if its losing spark of fuel?

No I'm not sure at this point which it is....
Plugs seem to be sparking though. I pulled them out to check and when I cranked it I could hear them sparking

 

[Neutron]

Get some brake cleaner with the straw attached, remove the small breather hose that goes to the rubber boot before the throttle body. Either give it a long squirt then try and start. Or the better way is to have someone crank while you spray in the hole. If it trys to fire or does fire for a second you have a fuel issue or lack of fuel issue

 

[CaptRedbeard]

What role would the rectifier play in this? Doesn't it just convert AC from engine to DC to battery for charging?

@Ronnie mentioned it in this reply. Looking back he had an MR1 engine so possibly not applicable. The larger point is to start with the easier points of verifying air, fuel, spark. Newer motors typically have more electronics that make it more difficult to sort through.

 

[FLJetBoater]

@Ronnie mentioned it in this reply. Looking back he had an MR1 engine so possibly not applicable. The larger point is to start with the easier points of verifying air, fuel, spark. Newer motors typically have more electronics that make it more difficult to sort through.

Yeah I saw that but he said the rectifier failed. But I was just curious why that would affect it at all unless I am misunderstanding what the rectifier is for

 

[Ronnie]

Start with the inexpensive stuff IMHO. One of my Waverunners became hard to start a few years ago, until finally it got us out to our destination but it wither would not start or stay running long enough to get us back to the ramp, had to get towed back. It ended up being a bad starting solenoid, $30 online at the start of the pandemic and an hour or so to remove the bad and install the new.

 

[FLJetBoater]

Start with the inexpensive stuff IMHO. One of my Waverunners became hard to start a few years ago, until finally it got us out to our destination but it wither would not start or stay running long enough to get us back to the ramp, had to get towed back. It ended up being a bad starting solenoid, $30 online at the start of the pandemic and an hour or so to remove the bad and install the new.

I'm trying.....just seems the inexpensive stuff isn't so simple. When something starts and runs fine cold but doesn't when it's hot, makes it really difficult to troubleshoot

 

[73 vega]

Having this exact same issue! Did you solve it? I replaced the ecu and cam sensor and that didn’t solve it. Yamaha can’t figure it out either. Pulling my hair out!

 

[FLJetBoater]

Having this exact same issue! Did you solve it? I replaced the ecu and cam sensor and that didn’t solve it. Yamaha can’t figure it out either. Pulling my hair out!

Nope I gave up and took it in. Waiting to have it looked at

 

[motomark73]

Nope I gave up and took it in. Waiting to have it looked at

Any chance you have an update? My starboard motor does same exact thing, fires up great when cold, but have to crank it for up to 5 seconds before it sputters to life on a hot start. Port starts up immediately regardless of hot or cold start.

 

[FLJetBoater]

Any chance you have an update? My starboard motor does same exact thing, fires up great when cold, but have to crank it for up to 5 seconds before it sputters to life on a hot start. Port starts up immediately regardless of hot or cold start.

Not yet. Boat is in the shop right now. Also speaking with someone else on this forum who has the exact same issue and his has been escalated to Yamaha corp. No concrete diagnosis yet just a whole bunch of excluded items so far.

 

[Yamijunkjones]

Alright guys, 2017 ar195 having same issue. Yamaha boat tech by trade and this is really stumping me and Yamaha reps.
Check out my thread I’ve started on this issue

https://jetboaters.net/threads/hot-restart-issue.42237/

 

[FLJetBoater]

Alright guys, 2017 ar195 having same issue. Yamaha boat tech by trade and this is really stumping me and Yamaha reps.
Check out my thread I’ve started on this issue

https://jetboaters.net/threads/hot-restart-issue.42237/

Crazy all the reports of this all of a sudden?

that’s at least 4 in the last month.

 

[dzeppos]

Crazy all the reports of this all of a sudden?

that’s at least 4 in the last month.

Same here with my 2016 242 - its manageable but never had this issue before with the engines stalling after running hot on a hot day.

 

[motomark73]

Re posting my comments here from another hot start thread....

Mine is worse when wake surfing also. My current theory is higher loads cause higher running temps exacerbating the situation. I found some related Yamaha ECM threads for outboards on The Hull Truth. I'm assuming their ECM control logic is at least similar. The basic premise is either a relay or sensor is beginning to fail short and drawing down the 5V signal for all ECM inputs, making it nearly impossible to troubleshoot. ECM will allow motor to keep running even as there is a "developing" issue as the heat induced parasitic loss in the bad component pulls the entire ECM 5V baseline down. When you shut motor down and try to hot start, the ECM is now below 5V; there may be more stringent controls in place that wont allow motor to start or possibly you just end up with a calculated fuel and spark timing based on bad system voltage that just won't support ignition. As motor cools, the failing component starts acting normally, the parasitic loss on the 5V baseline goes away or gets to a threshold where the calculated value falls into normal range as if you were back a 5V baseline and all control logic begins working again. Not sure if there is any merit to this, but it could explain why it is so hard to troubleshoot. The parasitic loss on 5V baseline could probably be any # of components or even a poor ground in a harness somewhere.

What makes it especially difficult is something like a relay that only exhibits the poor electrical condition when above xxx degrees... you can bench test the component when cold and it will measure normal for conductivity, resistance , etc so you never find anything.