Yamaha 50 4 stroke

[Redfish7873]

Hi I have a 2005 yam. 50 4 stroke low hours (117)... Seems to get up on a plain and then starts to spudder and looses rpms then the temp. Alarm starts to sound..... Where should I start?

 

[JustJason]

Re: Yamaha 50 4 stroke

its 2009... is this motor still on it's original water pump??? All overheats/overtemps diagnosing should start at the water pump.

 

[Triton II]

Re: Yamaha 50 4 stroke

Also check the inlet passages on the lower leg are clear. Do you get a decent tell tale of water from the pee hole on the right underside of the cowl? Run it on muffs to check - no tell tale or spluttering tell tale = either blocked inlets or unserviceable impeller.

 

[rodbolt]

Re: Yamaha 50 4 stroke

are you sure its overtemp alarm?
the same tone is used for water in the fuel,if equipped.
low oil,low battery and a few other minor issues.
is this motor a fuel injected model or a carburated model. 2005 was the first year of the EFI 50 four stroke.
post the model number and we can say for sure,mostly

 

[Redfish7873]

Re: Yamaha 50 4 stroke

Not completely sure if it's the temp. And the kicker doesent feel that hot but, the temp. On the LCD panel shows the temp indicater. It is fuel injected... I am going to drain the fuel and check the water seperater....

 

[99yam40]

Re: Yamaha 50 4 stroke

http://forums.iboats.com/showthread.php?t=250876

 

[Redfish7873]

Re: Yamaha 50 4 stroke 2005 model number f50tfl (I think)

Re: Yamaha 50 4 stroke 2005 model number f50tfl (I think)

Hi I have a 2005 yam. 50 4 stroke low hours (117)... Seems to get up on a plain and then starts to spudder and looses rpms then the temp. Alarm starts to sound..... Where should I start?

Ok, I have changed the fuel filter, water seperator,fuel lines,had the injectors cleaned and added new fuel.... Nothing has worked so far, still spudders and the temp. Sensor still sounds.... But I have a good strong tell tale stream? A lil help would be awesome... I need to go fishen'!

 

[samueleric]

Re: Yamaha 50 4 stroke

I have the the 60hp which is the same motor on a Stacer 460 and couldn't be more impressed. When I was researching these I could find nothing but excellent feedback. I get around 8-9lph at cruise 4200rpm and 20 knots but varies depending on conditions and load. Never fails to start 1st go hot or cold, and uses no oil between changes.

 

[Triton II]

Re: Yamaha 50 4 stroke 2005 model number f50tfl (I think)

Re: Yamaha 50 4 stroke 2005 model number f50tfl (I think)

Ok, I have changed the fuel filter, water seperator,fuel lines,had the injectors cleaned and added new fuel.... Nothing has worked so far, still spudders and the temp. Sensor still sounds.... But I have a good strong tell tale stream? A lil help would be awesome... I need to go fishen'!

Hmmm, Rodbolt to the rescue methinks. Just a thought, from memory the temp sensor is in the water jacket under the cowl. If it's triggered I wonder if the motor goes into limp home mode. Dud sensor perhaps? Not sure about the F50 but the bigger EFI Yams have the limp home mode.

Another scenario is a partially blocked fuel vent in the fuel cap. As the engine tries to suck more fuel it can't do so against the vacuum being created in the tank. Engine starves of fuel, leans out, runs hot and splutters, alarm sounds. Boat slows down, driver selects idle, fuel requirement reduces, cap vent slowly lets in just enough air for the tank vacuum to reduce and motor runs OK again until the driver guns it again. Anyway, enough surmising, Rodbolt should be along shortly... to bail us both out!

 

[Redfish7873]

Re: Yamaha 50 4 stroke

I will check on the sensor but I'm starting to think it may be a vacume problem... I noticed when the motor is running the primer ball is not firm, it's not flat either just soft.. I thought the ball was to be firm when running? Iwill check the tank and vent for any problems...much thanks
and I'll get back soon.

 

[cousinabe]

Re: Yamaha 50 4 stroke

have you changed/tested the tstat? does that motor have a poppit valve?
is the head hot to touch more than 3 seconds?
does disconnecting the pink wire at the temp sensor turn off the alarm? does the temp sensor test in spec?

post the full model number off of port bracket to help us identify the motor.

 

[Redfish7873]

Re: Yamaha 50 4 stroke

I have not tested the t-stat... I can't seem to find it, I don't have a manual or schm. Poppit valve? As far as being hot to touch, it doesent seem to be that hot to me but the oil filter does get pretty hot, not to where it would burn though... I ran out of daylight today but, will check the temp sensor tomorrow.... I did check the tank and vent and dident find anything obvious but, I really don't know what I'm looking for. Thanks for the help guys, this is saving me much money I'm sure. Be back tomorrow! Model number f50tlrd. 6c1 L 1002278.... Thanks again!

 

[99yam40]

Re: Yamaha 50 4 stroke

You need to buy yourself a Yamaha service manual or take it to a Yamaha tech. You will not be able to get all of the info you need the way this is going.
As you have said you do not know enough about this motor to understand what is being given to you. Looking at things and not knowing what you are really looking for will not help.

You need to be testing things in a logical manner to eliminate certain things and then move on to the next step of testing. The manual will give you this info and hopefully you will understand what you are reading, If not then come back and ask.

 

[rodbolt]

Re: Yamaha 50 4 stroke

if an audible is set it will go into RPM reduction, if your getting a temp indicate on the tach I would look at the tstat,pressure control valve and the water pump.
a run with the laptop or the diagnostic test lamp will show what is triggering the alarm.
that ECU wont record an overheat but will display it while its active.
that engine also uses a temp sensor,not a switch,that can fail and needs to be tested as per the service manual.

 

[Redfish7873]

Re: Yamaha 50 4 stroke

Well guys thanks for all the great advice but, I think it's time to throw in the towel and seek a pro to do the work. I really need to get back on the h2o! If you all should ever need any advice from an executive chef drop me an email chefshanec@gmail.com. Thanks again