Evinrude 30hp 1988 idle and surge issue

G.day there
Secondhand motor serviced before i bought it should be fine but:
-idle is really rough and mixture screw not very convincing operation, cuts motor when all the way in (thats ok i think) but only idles up a bit and then cuts motor out after about a turn out. My exp of these on motorbikes is that the engine idles up quite high on the lean side then gradually falls away and cuts out with increading lean. At sea the engine is fine at full throttle and power ok but on part throttle it starts to lose power and revs all of a sudden and then cut back in and so on. Any ideas?
Two things ive looked at are the fuel pump, the diagphram is intact and should be ok and the carb has been off and looks clean. One thing is that my Seloc manual suggests that there is a tiny plastic bearing that goes over the tip of the idle needle to centre it but the dealers here say it doesnt exist. Anyone know if it should be there? This could be a synchro issue too cause i set it as per Seloc but this is not very specific for my exact model.
Ta Roj

Re: Evinrude 30hp 1988 idle and surge issue

Welcome to iboats Roja!

First, let me turn you on to the BRP link. Click on "View Parts Catalog" and follow the prompts. You should have your model number handy. You can get in there and see a parts break down of the carb.

http://epc.brp.com/login.aspx?ReturnUrl=/default.aspx?brands=ej&lang=E&brands=ej&lang=E

That little plastic needle bearing didn't last long and was used way back in smaller engines. Your carb does not have one. But it should have the friction ring in the front of the hole where the needle goes in and should give you resistance when you turn the needle. The starting point is around 1 1/2 turns out from GENTLY seated.

One or two things to do, get the OEM carb kit and give the carb a good soak and cleaning. Apprearances can fool you.

Another thing that may cause some of your problems is the gasket that seals the nozzel from the bowl well. If this leaks, it can cause flooding of the carb and very poor idle. It's part #7 on the parts breakdown.

And do make sure the fuel lines are still flexible. Hard fuel lines can lose their grip on connection points and suck air.

Take a look at the diagram and see what ya' think. Stay in touch with us.

Re: Evinrude 30hp 1988 idle and surge issue

Sure sounds reasonable, I will hoick the carb off again to start and have a good look at that base gasket and if all fails, order a kit for it. Gonna be a trial of elimination perhaps. Ta for reply its great. Roj, on the shores of sunny Rockingham, Cockburn Sound Perh

Re: Evinrude 30hp 1988 idle and surge issue

Still not running like it should.

Had a good look at the carb, seems ok.. Im thinking that the issue is lying with the synchro and my aftermarket manual isnt showing the correct procedure or something? One thing is doesnt show is the way to do this with a remote conversion fitted on original tiller steer engine. There is a grub screw on the linkage that affects where the butterfly begins to operate, maybe thats a part of it..
Any one know how that is set?

Re: Evinrude 30hp 1988 idle and surge issue

Pretty easy Roja.....

The roller rides on a cam. The movement of the cam pushes the roller which in turn opens the throttle plate.

Look at the cam. You will see a reference mark....like a "V" notch. When this notch is centered on the roller, the throttle plate should just start to open.

On the starboard side of the carb is a lever with a slot in it. An adjustment screw goes through the slot. Losen the adjustment screw and adjust the lever to get the correct throttle plate opening setting.