70 hp evinrude with a bad idle

This has been troublesome the last year. I took the carburators off and completely cleaned them thoroughly. And I installed new plugs. My next step is to change the fuel filter this year. What am I missing? So in other words; What would the dealer charge me $1000 for that I should have seen?

This could be a lot of things. New plugs? Old fuel? Could be water in your fuel. Changing the fuel filter is a good idea. Rebuilding the fuel pump should be cheap and really easy also. I would also try running some Sea Foam through it, mixed in your fuel. How many RPMs are you idling at? Might just need to adjust your idle speed or the fuel/air mixture on the carbs. Plug wires rarely go bad.

Could also be a bad coil.

I run sea foam through every and a few in between. What are some symptoms of a bad coil or weak pump? When the motor is run for its first 20 min its slow to catch up to the throttle postion. And when it does catch up she revs and I’m quick to pull the throttle back. I have a brand new coil for it I guess I could try quick. I bought the coil on accident a couple years ago. Thats a long stupidity story.
Hey thanks guys I’ll make sure to go over all of the above before I give up.

We had some problems with our 40 hp. evinrude outboard last summer. First it started out like it was just idling bad then it got worse and would die and stop running. We talked to guys at a marina and we ended up buying a new fuel line and filter, because if you have cracks in your fuel line air will get in and it won’t suck the gas as well. Anyway, if something like that doesn’t work like for us you’ll have to take it in to a mechanic, unless of course if you have the knowledge yourself, and have it checked out. Our’s ended up being nothing with the fuel actually, even though every body thought it was, but it ended up being that the fly wheel came apart. A few bucks later and it ran great.

Hope this helps,
red89

You had me all excited there for a second. The bad fuel line scenarion was exactly what I wanted to hear and then you killed it at the end of the post. But….. if the mechanic said it was a possibilty then it probably was.I’m just praying I figure this out before opener. And I hate taking things to mechanics. Do you think I could take it in,…have them see whats wrong just to find what, and then do it. I’m mechanically literate but I just don’t have the time to be fartin around with this. Thanks again

matt thats not a bad idea but sometimes they also go through a process of elemination to find the problem. Are you sure the air and gas mix screws are adjusted right. If theres a vacume line on the motor get a vacume gage and set the air mix screw using the gage. When you hit maximum vacume stop there. If there isnt bring to max rpms by backing the screw out then back in 1/8th of a turn on each carb. If it has coils under the flywheel check for thier clearance, they should be as close as you can get them, about 15 thousandths. If its electronic ignition it might be eigther the plugs, carbs, timing linkage on the carbs, maybe wireing connections. Also check for worn bushings in the linkage. Gap the plugs, check the screws in the carbs again and if that dosen’t do it check everything from the coils too the carbs again. When you worked on the carbs did you soak them in lacquer thinner or carb cleaner then blow them out with high pressure air? The air passages have got to be clean for the right air mix or it will run like your saying. The way too tell is when you turn the air mix screws the engine will immediately fall or raise in rpm’s, if it dosen’t go back through the carbs and clean them throughly and make sure the float is set right or they will run lean or flood. The float has to be right also. Take your time and double check everything. Look for any bare wires under the flywheel that might have wear on them, ive seen afew of these without insulation and they would short out. Double check the points, wire connections, everything. If you get it running , run it at night or in a dark place and check for sparks via shorts in the wiring. This is a good time to find out what shape the plug wires are in. Look for very faint sparks that you have to look twice and very close too see.

I would do a compression check as well. I had a Evinrude 70 that was idling weird and would start off slow and kick in after a few seconds…ended up blowing motor! Had a bad head gasket!

I put a new fuel filter in yesterday. I took the old one off and blew through it, and then blew through the new one and I could tell a distinct difference. How much resistance do you think it takes until it screws the amount of input fuel up?

A bad/plugged fuel filter shouldn’t effect idle, if the mid to upper range rpms run good. Meaning that if the filter is plugged and won’t idle, the motor won’t run at all once gas is applied, because it will starve out…….

If the motor isn’t idling right, check your fuel/air mixtures and your timing. If you can’t fix it, then I would recommend taking it to an experienced mechanic.

Good luck!!!