Yamaha f150 hiccups every 35 sec. regardless of RPM....Cured!

[snorkelbob]

As the subject line says I have had this problem for the last 2 years or 200 hours run time. I had asked for help but this was quite the stumper on all forums. Just 2 weeks ago I prepared for another season of boating. I had resigned myself to live with this hiccup as it never got worst. Well I have no idea if the problem disappeared on it's own or my cleaning the injectors fixed it , but it is gone . I was so used to it that it took me till my 3rd boat ride to realize I had no more hiccup. Just thought I would share that as so many members tried to help me with this 2 years ago. Thanks again for your help. This remains a mystery in my mind anyway.

 

[Harper]

I remember that ..... strange. Glad it's feelin' better now, though.

 

[Dave LeGear]

Injectors with poor spray patterns can cause what feels like a electrical miss. Also, if you are against the RPM limiter, the ECU can shut down injectors to help prevent a over speed condition that though, is a lot more violent, but will also feel like a electrical miss.

Flip side of the coin, and this episode reinforces my saying (that known good is even better than new) I had spark plugs cause the same issue and even had a brand new just installed plug (NGK how rare is that) create the same condition. Now that one will make you shake your head and get this..., it never did when running it on the muffs... You had to always have the boat in the water and under load to duplicate it. The Second set of brand new plugs corrected the problem though.

As far as injectors go, Chevron's Techron product in a bottle (what Yamaha calls ring free) in the clean up version, poured into the fuel tank does a good job at cleaning up injectors. We used it a lot back when I worked with Porsche and BMW many, many, moons ago. The only thing I would be mindful of, is that it is hard on engine oil since all the crud (carbon deposits) it can cut loose, winds up into the crank case to then start circulate inside the engine. As such, I would not run more than 3 bottles in a row in 3 tanks of fuel without preforming a oil change...

 

[snorkelbob]

Thanks for the replys guys. I use techron fuel injector cleaner and the much stronger Ringfree on a regular basis. Must be doing some good as this has been my only issue so far. Still the thing I have a problem understanding is the 35 sec. regularity at any and all RPMs. Just glad it is back to normal now. Thanks again.

 

[Dave LeGear]

Thermodynamic type of breakdown of some kind is also possible. So is a programming glitch in the ECU. Both "can" be caused due to a circuit breakdown due to heat, this along some part of the electrical system that is dropping voltage.

ECU's are very sensitive to operating voltage and once below 10.5 volts (for a better lack of terms) loose their mind and drop into a limp home static running (meaning no timing advance) mode

So anything from a coil breaking down, to low battery voltage / drop in charging, is what I have found many times... Loose or dirty ground wires are a common culprit... I say clean and re-secure all the ground wires, as well as, check all the harness connection points on the engine, as well as battery or battery switch connection points just to make sure. I would also fire up the meter and watch certain connection points including the battery voltage, while it is running...

Salt crud and banging on the engine while launching off waves, all can be the cause and it does not take much if a air gap on a grounding or connection point to cause all kinds of little strange Voo Doo things to happen and effect engine performance.