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Quickly dies after restart

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berkmda

New member
Hi - have a 2015 25hp tohatsu 4 stroke. Runs great upon initial start, runs 30 min or longer no problem snd never stops. Once turn off and then restart it the engine quickly dies after just 2-3 seconds and won’t start again for hours.

I checked injectors snd cleaned. Replaced the idle control valve. Replaced water pump, but does same in driveway when cooled by hose also.

ideas??
thanks!!
 
So is your model MFS25B or C?
Sounds like a thermal issue. Have you checked the spark and injector and FFP signals coming out of the ECU?
Why swap the ISC valve? Why change water pump?
Have you checked temperature with an IR thermometer?
What is the oil level on the dipstick?
 
pvanv said:
So is your model MFS25B or C?
Sounds like a thermal issue. Have you checked the spark and injector and FFP signals coming out of the ECU?
Why swap the ISC valve? Why change water pump?
Have you checked temperature with an IR thermometer?
What is the oil level on the dipstick?
Click to expand...

First, thank you for response!!
i changed idle control valve on recommendation of someone who “knew the problem”, obviously not. Water pump needed to be changed, just did to ensure wasn’t a cooling thing.
yes it has spark when it wont start. Just ran for 15-20, turned off, started it and run for 4-5 seconds and sputtered out. Now wont start again for hours, but eventually will just crank right up and run perfect until i turn it off.

i didnt check any other signals, not sure how. Something written on what to check? I have a meter.

it did have a bit of a fuel smell when it wouldn’t start again, but bulb is still tight. When i restart later i dont need to prime, just crank and turns right on. Maybe 3-4 hours.

thanks!!
 
pvanv said:
So is your model MFS25B or C?
Sounds like a thermal issue. Have you checked the spark and injector and FFP signals coming out of the ECU?
Why swap the ISC valve? Why change water pump?
Have you checked temperature with an IR thermometer?
What is the oil level on the dipstick?
Click to expand...

and it’s a MSF25C
 
Sounds like a problem with the ffp and associated wiring. Check for 12v to the pump on restart.
 
pvanv said:
Sounds like a problem with the ffp and associated wiring. Check for 12v to the pump on restart.
Click to expand...

Getting 14v to 3DA6ED7F-EE0F-46F9-A068-443219C0DBB8.jpg the pump, measured at this connector both when starting cold and after running for 20 min and then trying to restart and quickly dies, still had 14v.
what is interesting is i disconnected that connector and started it, ran for 3-4 seconds and died. Restarted and ran for 1 sec. It did exactly what it does, same exact indications, as when it wont run after trying to restart.
I did check the injectors earlier after it wouldn’t restart and gas is spraying out of all three even when it wont start. Also has spark.

other thoughts? Thank you!!!!
 
pvanv said:
Your ffp may be getting jammed. Do you hear it pressurize when the problem happens?
Click to expand...

thank you, will check.
if I pull off the injectors would they not be spraying if jammed? Thinking I should try that again when it doesn’t start and see if gas is spraying?
 
Paul,
starting to think it is the fuel pump. The unit the pump is in (evaporator?), should that be getting pretty hot? Like very hot to the touch?

After it wouldn’t start took the injectors out and no gas was spraying. Waiting a couple hours and then gas was spraying. Just ran the engine for an hour and it restarts fine but after 3-5 seconds it idles down and is very rough almost dying but continues to run poorly. When putting in gear at fast idle speed Varys some and eventually settles down.

FFP??

looks like a $50 part and a bit of work to pull the unit and replace the FFP inside. Does that sound like its my problem? I also was able to download a MSF25B service manual, can’t find a MSF25C. What is difference from B and C?

after market FFP ok to go with if that is your recommmendation?

thank you VERY much!!!
Dave
 
Looks like the FFP is $410 or whole evaporator assembly which I assume has FFP is $698.

If you believe FFP, get whole unit or just FFP? Any recommendations for where to find a better prices?
thanks!
 
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