2004 75hp Mercury outboard wont idle

[carcrazy]

I have a 2004 75hp Mercury. Compression is good, timing is checked, but when starting up engine RPMs goes very high then i have to slow it down then the engine stalls. The carbs were cleaned prior to purchase. Anybody have any ideas on how to repair this?

 

[DamianJP]

Re: 2004 75hp Mercury outboard wont idle

Hey carcrazy

Does the RPMs on start happen by them selfs (like a surge) or are you talking about only being able to start it with warm up bar up for higher RPMs? Then when you drop warm up back down she can't hold an idle?

If they cleaned carbs prior to purchase they 'should' have checked from tank to carbs on the fuel delivery, but check them anyway. If you just bought the motor check tank , filter, lines(primer bulb too).

Mabey it's a simple idle adjustment on carb.

After that the check the carb that was rebuilt.


Lemme know,
DamianJP

 

[carcrazy]

Re: 2004 75hp Mercury outboard wont idle

Thanks for the reply,with warm up bar all the way up it starts and goes to high rpm right away ,Fuel delivery is good source .My next move will probably be to take carbs off and check them oh it stalls when i move bar down to idle

 

[DamianJP]

Re: 2004 75hp Mercury outboard wont idle

Hey again carcrazy


Also do you know if the fuel pump is 100%?


After that I would recommend re-doing the carbs like you said.

Is there anything to tweak on the carbs like an idle screw or any other adjustment? Or just fixed jets?

Check for crap in the bowl and everywere else.

Check if float range of motion is smooth and not sticking.

Check the float's hanging level and make sure it's into spec. Sometimes the metal arm gets bent abit either letting in too much or too little fuel.


Lemme know,
DamianJP

 

[carcrazy]

Re: 2004 75hp Mercury outboard wont idle

Damian, The carbs have a idle screw there out about 1 turn from seat,I will check fuel pump and carbs ,I guess I was trying to fix without disasembling ,But your right I will dig in some more it may be awhile until I reply this is a no hurry project my 90hp chrysler is still on boat until I get this one going .Thanks ,Frank,