Motor only runs whith choke on

[mobytodd]

1985 evinrude 40hp. I have cleaned the carbs ran, new fuel lines, cleaned the fuel pump... I am at a loss as what to do except rebuild the carbs and rebuild the fuel pump. any ideas guys?

 

[tashasdaddy]

Re: Motor only runs whith choke on

you've got it. right on track.

 

[mobytodd]

Re: Motor only runs whith choke on

So I should rebuild both????

 

[Evinrude Boater]

Re: Motor only runs whith choke on

Isn't he getting too much air in a loose connection, thus choking reduces the air coming through the venturi?
Did the motor run properly before working on the fuel system?

 

[tashasdaddy]

Re: Motor only runs whith choke on

agree check for leaks, no since in only rebuilding one, how do you know which is bad. if they've never been done, overdue.

 

[mobytodd]

Re: Motor only runs whith choke on

No the boat didnt run before. I am trouble shooting the thing right now. I think I am gonna check for loose hoses and start there. I will keep this thread open incase it is not that. Thanks.

 

[F_R]

Re: Motor only runs whith choke on

Almost certainly dirty carbs, especially the high speed orfice jet in the bottom of the carb bowls. Those are right down there where fuel lays and turns to gum. Result is you have to keep choking it. A very common problem.

 

[jay_merrill]

Re: Motor only runs whith choke on

Carb rebuild couldn't hurt and is a good idea if the motor is new to you, since you don't know when it was run last. If you rebuild them and you still have the problem, try smearing some grease on the external portion of the throttle butterfly shaft wher it meets the carb housing - there is sometimes wear in this area, which will cause the carb to suck air in. The grease may block that temporarily and aid in troubleshooting, but it isn't a long term fix.

 

[samo_ott]

Re: Motor only runs whith choke on

If it only runs with the choke on, then it is not getting enough fuel in a normal situation and is probably the low speed side of the carbs. So I concur, check for air leaks and then rebuild em.

 

[Evinrude Boater]

Re: Motor only runs whith choke on

You might see fuel leaking out the side of the carb at one of the plugs or other holes or the gasket at the intake manifold may be faulty.

 

[georgiaboy]

Re: Motor only runs whith choke on

why does'nt he do a decarb if he can keep it running-wouldn't that get the gum out of the carbs without a rebuild? Just wondering.

 

[mobytodd]

Re: Motor only runs whith choke on

What is a decarb?

 

[HighTrim]

Re: Motor only runs whith choke on

why does'nt he do a decarb if he can keep it running-wouldn't that get the gum out of the carbs without a rebuild? Just wondering.

No, a decarb does not take the place of a carb rebuild.

Mobytodd, see the FAQ for the decarb instructions.

 

[samo_ott]

Re: Motor only runs whith choke on

A decarb takes the carbon out of the cylinder, pistons etc... Search on decarb on this forum and you will find plenty.

The carb clean and rebuild takes the gunk and old solidified gas out of the carb and teeny tiny holes in the carb to let the fuel flow where it's supposed to flow and make the engine run how it's supposed to run...

 

[mobytodd]

Re: Motor only runs whith choke on

Thanks. When you guys say rebuild... You do mean put a new kit on them... right

 

[samo_ott]

Re: Motor only runs whith choke on

Yep. Take the carb(s) off and apart and clean and replace all the seals, gaskets, etc with a carb kit. In the older models it took longer to re and re the carb then it did to rebuild it.

 

[mobytodd]

Re: Motor only runs whith choke on

Steve I am so new to this till... LOL I have the carbs off now and I am awaiting the rebuild kit. I am soaking the carbs themsleves in seafoam to maybe break up any build up they may have internally.... Once the kit comes in then I will reassemble and see what happens.

 

[rockyrude]

Re: Motor only runs whith choke on

Before you put everything back together, blow all the pasages out with a compressor. The rattle cans won't work.

 

[Evinrude Boater]

Re: Motor only runs whith choke on

I could be wrong but I'm not sure Sea-Foam will do the job. When used in an engine it burns off carbon after soaking. Carburetor cleaner works miracles and you can spray it into the orifices. It's formulated to break down varnish from old gas. I agree with the recommendation of using compressed air. Mine didn't work properly until I blew it out and something caming flying out of the carburetor and hit me in the face. Wear your safety glasses!!!

 

[georgiaboy]

Re: Motor only runs whith choke on

is there a cleaner you can put it the gas that will clean out any resident gunk even though the engine may not be to the point of having to run on choke- like a spring cleaning so to speak??