Peter G

[pcgreen101]

Hello, I have a Yamaha F150 4 stroke, 2005 mod, outboard idle was 1100 RPM and would bog down under throttle. Replaced Pulsar coil assembly but same prob. Replaced ignititon coil same prob. Replace fuel pump and reg same prob. Changed fuel same prob. Last test run after adding earths to ECU and further around the harness the outboard still wont rev out and has fluctuating idle and will stall sometimes, flashed air temp sensor and map sensor that has also been replaced. Has any one got any plan of attack, thanks. PS codes have been reset by de-powering plus and leads have also been replaced. pcgreen101@aapt.net.au

[99yam40]

flashed air temp sensor and map sensor that has also been replaced. Has any one got any plan of attack, thanks. PS codes have been reset by de-powering plus and leads have also been replaced. pcgreen101@aapt.net.au

Not sure what you mean by
flashed air temp sensor and map sensor
or
PS codes have been reset by de-powering plus and leads have also been replaced

It would be best to get it hooked up to a computer for diagnostic, throwing parts at it gets very expensive.
Read all of Rodbolts17 posts on the F150 to see if you can get what you need out of them, he is a master tech, but has not posted in some time now.
Seems like I remember him saying something about high idle caused by failed sensor of some kind
See if you can find a local Yamaha shop with a Yamaha master tech

[TownsendsFJR1300]

F150

Check and make sure your plastic fuel filter housing (located at the front of the engine with a sealing 0-ring) is fully seated. I had mine replaced under warranty as it expanded (due to the crappy fuel nowadays) and wouldn't seat fully. Not seating fully caused a major air leak in the system.

Also, drain (on the starboard side) the fuel from where the Fuel Injection pump resides. Catch it in a small container (I use a clean tuna fish can) and check for water/crap... Prime the bulb and flush if more comes out. I would also blow back gently (by mouth) and get more crap out, flush again...

I would also sync the throttle bodies if it hasn't been done.

It sounds as if the fuel injectors also may be clogged. You have fuel pressure getting to the injectors but if their clogged somewhat, it'll cause irratic operation.

Have you used fuel stabilizer in the past (as fuel will go bad in as little as a month)?

Seafoam works fairly well, I found a product that works very well at helping to remove moisture in the system and clean the system: K100 Fuel Treatment : Fuel Additive, Fuel Saver

I have the same engine as you and had some moisture make it to the FI pump (and found it while draining as mentioned above). Being a built in 50 gallon tank in a 1997 boat (never removed the gas tank), I preferred not to remove it. The K100 will suspend the water and keep it mixed so it'll burn out with normal running. It also cleans the fuel system/valves, etc, EXCELLENT product IMHO. My engine now idles at 700 RPM and has absolutly No bogging what so ever...


Good luck

[pcgreen101]

Thanks for your thoughts, I have drained the vaporizer and checked the level of the float. I will check for leaks as you said, on the clear water trap at the front of the motor. I will add fresh fuel to external tank and try also, once again thanks for the information, I will let you know how it goes.
Peter G

[coueytwo]

I just had to replace the ISC on my 2003 F115, was doing high idle from 1100-1600 RPMS, replaced the ISC it went to 700 RPMS. It's something to check for.

[pcgreen101]

Fixed

well, after much time and electrical component changes , shear desperation led me to question the mechanics injector clean job that cost me $260.00, I got reco injectors for $140.00 , plugged them on and my outboard was fixed. Never rule out somebody's incompetents. Pray the lord.