Yamaha 2008 F 115 HP running very badly,.....

[wildman07]

To all, Please help,

I have a 2008 F115 Yamaha four stroke with 345.0 hours on it from new. I purchased the engine brand from the dealer.
Serial # F 115 AET L
1102365 G
68 V. L 09/08.
It has been some what of an okay engine up until now. We have had the on going issue with the engine making oil, which Yamaha really does not seem to care about at all. I have changed props several times, done the ring free thing, changed the thermostat, tried everything, but to no avail. The engine still makes oil, this I can live with it just means we change the engine oil every 50 hours.

The worst part now is that the engine when started from cold starts slowly and idles like it's only on two cylinders. When it's put in gear and put under load it gets worse.
The compression on each cylinder equal 150 psi evenly.
The fuel pressure is 42 psi. With the key on. Running the pressure is 38 psi. Hot and cold there is no difference.
I have installed all new fuel filters ( rarcor fuel water separator, and the high pressure pump filter ) .
With the engine running at idle I removed one spark plug wire at a time and there is a change. With the engine in gear and around 1800 rpm # 2 and # 4 cylinders have no change what so ever when I remove the spark plug wire.
Once again at idle I disconnected 1 fuel injector at a time which made a difference on each cylinder. I also did this with the engine running at 1800 RPM again cylinders # 2 # 4 no change in tone.
So did the spark plug wire removal again on each cylinder at 1800 RPM. I notice I could hear no spark jumping when the wire was removed away from the plug. # 1 and # 3 when removing the spark plug wire you could hear the spark jumping to the plug.

I'm thinking the water pressure sensor could be bad, but I don't want to spend $ 354.00 if I'm wrong.

I also have three F 250 Yamaha which knock on wood have never given any problems.
I also have a Yamaha V max 150 HP, along with Yamaha 200 2 stroke and. Yamaha F 25 , so I'm no stranger to the Yamaha product.
I will add how ever this Yamaha F 115 HP has been a huge dissapointment. And now this running problem is driving me nuts.
The dealer has been no help and offers no warranty on out island engines. Yamaha U.S.A. Has been less than helpful.

Any advise would be great, I need this work horse back in the water and operational.
Thanks to all that can assist.

Bill

 

[renegade15]

Re: Yamaha 2008 F 115 HP running very badly,.....

Sounds like you isolated that plugs #2 and #4 have no spark to them. Have you tried a new ignition coil? As a test you could switch the coils and see then if the no spark problem is replicated on cyl 1 and 3 instead of 2/4? They also make an inline spark tester that are not terribly expensive, though getting to you might be more of the problem...too bad it's not may still, my parents were just in the exumas most of april and may on the cat and my dad is great with this kind of stuff! Good luck!

 

[wildman07]

Re: Yamaha 2008 F 115 HP running very badly,.....

Sounds like you isolated that plugs #2 and #4 have no spark to them. Have you tried a new ignition coil? As a test you could switch the coils and see then if the no spark problem is replicated on cyl 1 and 3 instead of 2/4? They also make an inline spark tester that are not terribly expensive, though getting to you might be more of the problem...too bad it's not may still, my parents were just in the exumas most of april and may on the cat and my dad is great with this kind of stuff! Good luck!

The ignition coils on this engine are the same how ever # 2 is fired by the upper coil and # 4 is fired by the lower coil, therefore swapping them will not help.

I was lucky enough to use the Yamaha software equipment from a neighboring island today and discovered that the computer said there is nothing wrong with any of the sensors or the running operations of the engine are normal. Yet it still runs like crap. Go figure.
We set up a remote fuel tank with fresh fuel ( thinking it may have bad fuel ) but no change,...poor thing still runs like crap.

May be time to sink it and buy a good old Yamaha 2 stroke or a Suzuki,.....like I said earlier We are all pretty dissapointment down here with Yamaha 4 strokes and there oil making problems along with there crap back up service. Once they hit 400 to 500 hours they start giving all sorts of wierd problems. All the boys down in this area pretty much throw these engine away when they start giving problems. Sad but true.

Thanks for your help,

Bill

 

[99yam40]

Re: Yamaha 2008 F 115 HP running very badly,.....

Yamaha service manual will have the info and steps for troubleshooting ignition system.
That ignition system is something different TCI maybe they call it
Do you have one for your motor?

The computer may show sensors are not failed but an expert needs to look at readout as they can see things that are not normal.
Best to find a Yamaha Master tech to help troubleshoot your motor.

Might try searching for and reading posts on the F115 by Rodbolt here and other forums like yamahaoutboardparts (Rodbolt17)
He is a master tech

 

[smitty477]

Re: Yamaha 2008 F 115 HP running very badly,.....

Hello Bill,

Sorry for your problems. I am not a marine mechanic nor an expert on these Yamaha 115F engines but they can run well for many hundreds of hours with just normal maintenance if you can sort this out. We just sold a boat with a 2002 F115 Yamaha that we owned for 6 seasons (bought it used) and it had 1,400 hours on it and going strong. Only had to do the basic stuff with the engine each season but we did make a little oil between changes so we just filled it like 4-5 ounces short each time we did a change. I hope it works out for you I just wanted you to know that they can be very good if you can find a way to get past these current issues.
Hope this helps

 

[Bamacrusader]

Hey Wildman did you ever figure out what was going on with your Yamaha F115? My boat with the same Yami motor is having the EXACT same problem with cylinder #2 & #4 fouling spark plugs and doesn’t appear to be firing or burning all the fuel.

 

[GA_Boater]

Hey Wildman did you ever figure out what was going on with your Yamaha F115? My boat with the same Yami motor is having the EXACT same problem with cylinder #2 & #4 fouling spark plugs and doesn’t appear to be firing or burning all the fuel.

After being a forum member for 5 years you decided to post in an 8 year old thread. Maybe it's time to read our rules.

Closed.