Hard to start then rough idle

[dscable]

OK, I have an issue and I am out of ideas. Looking to you guys for some help.

Boat details:
2013 AR190, but has a 2016 AR240 engine, unsure of the hours (long story, but you can find the history by searching for "huge power loss" thread by member "Abovethebest" )

Facts:
Hard to start, warm or cold. Cranks for about 20 seconds before it will fire.
Runs very rough at idle, warm or cold, (lots of engine vibration) and dies at least 3 or 4 times after pushing away from the launch, especially if I try and apply any throttle.
have to idle for at least 3 or 4 min before I can apply throttle and take off without engine dying
Once running, engine runs fine at about 7600 RPM and seems to operate normally
I can run it across the lake for 20 min just fine, slow down to idle, let the engine cool off with the blower running, shut down and immediately go to restart....same issue....hard to start and rough idle.
Boat has had a check engine light since I purchased late last year, but unsure if/how I can read it without a YDIS.
No Wake switch does not work (not my main issue)

What have I done?
Replaced battery with brand new Group 27 Dual Purpose Duralast, fully charged each time before heading out.
checked all battery and starter connections (starter connection was loose when I purchased boat)
replaced No Wake switch
changed oil
changed spark plugs, replaced with OEM recommended NGK and checked proper gap
been through at least 2 tanks of gas with same issue
I had to replace the reverse gate cable because it was broke off clean at the gate, but shouldn't impact engine starting or idling

Thinking next step is SeaFoam (even though I have been through a couple of tanks) and possibly air filter....?? Saw SOME oil on one plug when I changed them, but wasn't soaked. Otherwise, plugs looked fairly normal.

Any suggestions would be REALLY appreciated, as I do not have a reliable dealer close and am headed out to Dale Hollow Lake for the July 4th holiday.

Thanks!

 

[JetBoatPenguin]

Try this trick on the hard start...it may be the fuel line pressure drops or is low. Try taking the key and moving it to electric mode (not full start) for 3 seconds, then turn it off...and repeat a couple of times. That may build pressure back up in the fuel line....and then try to start it.

If this does work...one thing you can do is check the fuel line pressure with a gauge and see how rapidly it drops. Should be a port somewhere (can't remember off the top of my head) and run the engine with the gauge attached (I think mine was $25 from an auto parts as store) to check the fuel line pressure if it's where it should be. Turn off the engine.
If it drops quick you know you have a fuel pressure problem. There might be a valve in the fuel pump that is bad. Basically the valve should keep the line pressurized, and if it falls it starts to let the fuel back into the tank or isn't sending it as it should.

I try to prime mine when it's been sitting a long time. ...which shortens the fire up crank time. I have to do this on my 17+ yr old truck as well....similar behavior to what you're describing. Priming it...fires up right away. I consider it "theft protection".

My second thought is that it could be the injectors....

 

[dscable]

Try this trick on the hard start...it may be the fuel line pressure drops or is low. Try taking the key and moving it to electric mode (not full start) for 3 seconds, then turn it off...and repeat a couple of times. That may build pressure back up in the fuel line....and then try to start it.

If this does work...one thing you can do is check the fuel line pressure with a gauge and see how rapidly it drops. Should be a port somewhere (can't remember off the top of my head) and run the engine with the gauge attached (I think mine was $25 from an auto parts as store) to check the fuel line pressure if it's where it should be. Turn off the engine.
If it drops quick you know you have a fuel pressure problem. There might be a valve in the fuel pump that is bad. Basically the valve should keep the line pressurized, and if it falls it starts to let the fuel back into the tank or isn't sending it as it should.

I try to prime mine when it's been sitting a long time. ...which shortens the fire up crank time. I have to do this on my 17+ yr old truck as well....similar behavior to what you're describing. Priming it...fires up right away. I consider it "theft protection".

My second thought is that it could be the injectors....

Thanks for the reply, I really appreciate it!

I am not sure the key position on my boat has an "accessory" position. Once the battery switch is on, all electrical components are up and available. The only thing the key really does is crank in the starting position. I'll go out here in a few and verify though.

 

[seanmclean]

First thing I'd do is buy or borrow a YDS and figure out what the CEL is for. May be somebody nearby who could help.

 

[rkluck]

Agree with the above you need to check your error codes since it may provide some insights.

 

[dscable]

First thing I'd do is buy or borrow a YDS and figure out what the CEL is for. May be somebody nearby who could help.

So, since the boat is a 2013 AR190 and the engine is out of a 2016 AR240, do I look for a YDS compatible with the 2013 boat or the 2016 engine?

 

[dscable]

So, since the boat is a 2013 AR190 and the engine is out of a 2016 AR240, do I look for a YDS compatible with the 2013 boat or the 2016 engine?

Anyone in the Indy area have a YDS that I can use?

 

[spatty99]

A bad o2 sensor can cause hard starts and rough running.

 

[Seadeals]

You would use YDS for the engine not the boat. The ECM followed the engine. What is your fuel history? Fresh or sat all winter etc.? Full tank of fresh ethanol-free or half tank from last summer? If they are not running smooth, I would also be checking compressions to know if there is a major problem before I risk blowing it up at 7600 rpm and getting a third engine. YDS is a good idea since you don’t even have to run the engine to get answers.

 

[tdonoughue]

I don't think the aftermarket YDS works on boats after 2012. You may need to take it to the dealer unless someone has found one that works on newer boats.

 

[dscable]

update - I think I have fixed the hard start issue. I was trying to start it in the driveway with the engine hatch open and caught a small glimpse of some white smoke coming from under the engine. Walked over and smelled "electrical" smoke. I checked the connection on the starter (had this problem before) and while it felt tight, it was burning the rubber boot so it was obviously arcing. I tightened it up a bit more cleaned up the connection and put some dielectric grease on it. Tried starting again and it fired right up. Still a rough idle and still has a CEL.

CEL - So.....figured out how to hold the "M" button down and get to the menu to scroll to the engine diag screen. Error showing is code 15 - which according to what I can find is "incorrect engine temperature sensor signal". NO IDEA where to go with that one. Started looking at the manual and see it listed, but can't find the part on partzilla for some reason. Anyone ran into that error code before?

 

[tdonoughue]

It seems to think that your engine temperature sensor is bad.

Likely the sensor is bad, rather than an overheat condition. Go to Yamaha Parts & Suzuki Parts, Motorcycles, ATVs & Accessories (or your other favorite aftermarket parts store), locate the temp sensor on the engine and replace that. Should be an easy install (wires out of it that disconnect, then unscrew, screw in the new one, put the wires on--if memory serves). Bet then it goes away...

 

[dscable]

So, an "engine temperature sensor" is not listed on any parts diagrams, is it the same as the Thermosensor assembly maybe? Part: 61A-85790-00-00 Yamaha 61A-85790-00-00 - Thermosensor Assy : Yamaha Sports Plaza

 

[tdonoughue]

Yep. I would say that was it.

Were it my money (and mindful it is not), I would drop the $80 on this and put it in to see if it cleared it up. I would give you at least 50% odds that is it.

It may not be, but if you go to the dealer or a marine mechanic, you are going to be out $200 for walking in the door. So I think this is a pretty good bet. Were we to actually diagnose it, I would say find a YDS to put on it (not available for your year at a reasonable cost). And then it tells you this sensor is not reading correctly and you replace it as the first diagnostic step.... before concluding the engine is running hot, and pulling it apart to diagnose the cooling system (not likely). So, this is not certain to fix it, but I am recommending what I would do first.

 

[dscable]

Yep. I would say that was it.

Were it my money (and mindful it is not), I would drop the $80 on this and put it in to see if it cleared it up. I would give you at least 50% odds that is it.

It may not be, but if you go to the dealer or a marine mechanic, you are going to be out $200 for walking in the door. So I think this is a pretty good bet. Were we to actually diagnose it, I would say find a YDS to put on it (not available for your year at a reasonable cost). And then it tells you this sensor is not reading correctly and you replace it as the first diagnostic step.... before concluding the engine is running hot, and pulling it apart to diagnose the cooling system (not likely). So, this is not certain to fix it, but I am recommending what I would do first.

Thanks, I agree with your logic, and just ordered it. I'll update the thread when it gets here and I get it changed out. Thanks again for the responses!

 

[dscable]

Update - The sensor seems to have taken care of the CEL. I'm headed out this evening to do a water test, I'll update the thread if the issue returns, but driveway tests showed success.