yamaha c115 loosing power

[cyrillefrenchy]

JB 123 thank's for your answer, i already check many times all the coils and wires, switch them with another engine, no succes.
i also cleaned the carbs and the fuel pump and replaced the complete fuel line.
like ROB says, i will try a rectifier tomorrow

[richardg]

TMD, thanks for the response. I'll check for the weak spark. What do you think may be causing a weak spark? or no spark at all?

Thanks,
Richard

[ROB]

I am not a mechanic, but paid to have my motor
serviced by two certified marine techs.I slow ***** fish alot and only #4 had weak spark and
all my carbs were checked the techs swapped cdi boxs mine was good. Under the fly wheel did need
some cleaning of the coils but was not the problem totally. A GM certified car tech buddy of mine actually sugested the rectifier as the source.He metered it some how and I bought one and installed it myself.No more problems!
I'm using a gas additive called sea foam which
helps greatly with the carbon build up, while fishing. Good luck Frenchy

[jb123]

please let us know the outcome.

[richardg]

ROB-the problem you and cyrillfrenchy describe is no power coming from #4. Do you think a bad rectifier will only impact #4 or do you think it could cause my # 3 cylinder to not fire?

Thanks,

Rich

[cyrillefrenchy]

hello richardg, when you say cylinder #3 "not firing" do you mean " no spark" or "spark but not working"?
frenchy

[cyrillefrenchy]

i have replaced today the rectifier regulator:no difference, still the same probleme, still de cylinder #4 not firing as strong as the others.
i am mad...

[richardg]

I want to thank everyone for helping me out with my problem. It turns out that my problem was with the carb. I didn't realize at first that each cylinder is fed by it's own carb barrel and for whatever reason the #3 barrel was completely clogged.

I will keep checking this site and offer any insite possible based on my knowledge learned from trial and error.

Richard

[jb123]

if compression and spark is good....whats left

[ROB]

Guess I owe a dinner to you cyrillefrenchy.
Have you ever load tested your starting battery?
That was a test they did on mine to check for a bad cell. The cdi box needs proper voltages and the battery may start the engine but put a strain on the electric system components if its bad.
Don't go out and buy a battery on my words, just pulling straws on your problem.

[cyrillefrenchy]

hi rob
i would rather buy you a big dinner...
i never tested the charging system but i can tell i have 2 1 year old batteries with a 3 positions switch and good clean battery cables terminals.i guess my charging system is working great because i never had to recharge the batteries even when i forget sometime to turn the navigation light off during 2 days.the starter always turn very fast and strong.i will check the charging voltage tomorrow and will post the result.
thank's again to all of you for your help

[Indy]

I want to help since I hade a simmilar problem once, first by a Clymer Yamaha Service manual $25.00 Aprox from West marine or any other boat shop. then do a resistance test on all your electrical components. Pay special atention to the CDI UNIT and the Trigger Coil (Pulser Coil) if any of them give you a reading different than the one on the book. Change the part.. GUARRANTEE IT WORK.....

[cyrillefrenchy]

hi all
i finaly checked the charging voltage at the batteries:
engine stopped since 3 days:12.30 volts
engine running idle :12.70 volts
engine running at 3000 rpm :13.50 volts
sounds good. right?
took the boat for a little ride, and after 1 minute at full throttle,seems like the rpm was back to 5300 5400 rpm, like before the problem happend.
back to idle,rpm at idle raised a little bit, around 1000rpm, was 800 850 before.!!!!!
surprised i opened the cowling checked again for the cylindre #4 : miracle!!! it works like the 3 others.
took the boat for fast ride again, better sound, maximum rpm ok,everything sound like ok.!!!!!
seems like the probleme is fixed by itself, i diden't not do anything.
i assume i am missing something somewhere, maybe bad electric connection?
any idea?
i will keep posting
frenchy