any marine techs out there? Merc engine issues!!

[Mr.Excitement]

hey guys, i need some technical assistance.

just wondering if there is anyone out there that can help me... or direct me to where to start looking at this problem...

my motor is a 2008 75HP EFI Merc.

anyone with pretty good knowledge... that can help me.... it would be greatly appreciated...

History.....

Had boat out last weekend. At the launch ... she fired up instantly... no problems.. ran absoulutely beautifuly... for a while... stopped and started it no problem... but on the way home, went to start it... and it turned over and over... sounded like it was going to start... then died...

tried to turn it over and nothing... just a click... i tried mutliple things, as battery and nothing more than a click... so i lifted the motor... and she was FLOODED... not sure if me constantly trying to start it.... flooded the snot out of it or not...

Now... i checked the starter, and it was fried... so i fixed that... it now turns over like a champ.

Problem is now... is like what happened before it died. it turns over and over and over... seems like it is going to start then chokes out. i pulled all the plugs.... and there was a ton of fuel still in the bottom cyc.... so i blew all of them out.... until they were dry.... cleaned the plugs... put it all back together.... then it starts first crank... then dies.

if i put the fast idle on... the engine will start and run like crap... the water coming out of the exhuast... has un-burnt fuel... it looks like... coming out.... shes puffing some black smoke too...

this engine has about 700 hrs, and has ran like an absolute champ until now...

too me it sounds like i have a cyc not firing... or the engine is getting WAY WAY WAY too much fuel.... with it being an EFI... should the ECM not realize that its giving WAY too much fuel???

anyone that can help.... if they want to PM me their number i will give you a shout!!

[Mr.Excitement]

also with the engine running like crap.... the idle is rough....

and the water jet out of the back.... isnt a constant stream... its a broken stream... but steady.... -.-.-.-.-.-.-.-.-......

[kawibrute750]

coil pack?

[pipes]

Sounds like the fuel injector on bottom rail is stuck open.swap injectors from #3 hole to 4th and see if problem moves .

[Mr.Excitement]

are the injectors easy to get at? i dont have the repair manual for this thing....

[Mr.Excitement]

Ok well... 1 cyc looks to be getting a ton of fuel... So we swapped the injectors around to see if that was it... And the same cyc was still over loading in fuel... So something is telling the motor it needs fuel when it doesn't...

All coils are ok and are firing... Very good spark, compression seems ok....


Thinking it is some sensor somewhere...

[Ziptie]

Originally Posted by Mr.Excitement

Ok well... 1 cyc looks to be getting a ton of fuel... So we swapped the injectors around to see if that was it... And the same cyc was still over loading in fuel... So something is telling the motor it needs fuel when it doesn't...

All coils are ok and are firing... Very good spark, compression seems ok....


Thinking it is some sensor somewhere...

Have you checked the compression in each cylinder?
You need to check each cylinder with the throttle wide open and that is definitely where i would start. If you don't have a compression tester you can borrow mine.

[pipes]

E.c.u sounds like the problem now.The .c.u. will give directions to the injectors or you have a faulty stator which no spark is happening causes fuel over load.Do u have spark on the flooded cylinder.Pull the ecm off and see if it smells burnt in behind.I think when the starter crapped the ecu was hit with a spike of voltage or something.Yes check compression also.

[Mr.Excitement]

compression is good on all.

Spark is great on all cylinders.

could be the ECM going to take it in, and get it checked... diagnostics should find it. unfortunately.