Only runs while hitting primer key

[cjbveteran]

1986 Evinrude E50 TLCD
Only stays running if I push the primer key every 10-15 seconds. New fuel tank, fuel lines, fuel pump, cleaned carbs twice, no adjustments to carbs can be made, new fuel filter, and new spark plugs.
Reving the motor up with the warm up lever doesn’t help, turning the red nob on the primer solenoid to keep constant gas just floods it out. Fuel line is connected straight to the fuel pump.
Any ideas before I put it in the shop would be great

 

[ahicks]

There's a few things it could be (vacuum leak somewhere?), but my bet is you're missing a set of jets hidden in the carbs somewhere.

 

[cjbveteran]

Ok I guess I’ll take them off again and look again but there isn’t much to these carbs

 

[racerone]

High speed jet is in the very bottom of the float bowl.------And when you use the primer fuel goes directly into the motor.----This fuel bypasses the metering circuits in the carburetors.----This would suggest ( to me ) that something was missed in your carburetor work.----Stop revving the motor up with fast idle.----That proves nothing.-----And post your compression numbers as well.----Perhaps as simple as throttle plates opening too early.

 

[Crosbyman]

tank vent open... does it run if you pump the fuel bulb to keep it alive ??

or is it just by choking/priming it every 10 sec. ?

 

[racerone]

If pushing the key in makes it come alive then I think fuel pump is working just fine.

 

[oldboat1]

I would disassemble and soak the top and bottom of the carb in the solvent of your choice. Open the core plug on top before doing so. After soaking, spray out all openings with carb spray, with special attention to the three holes under the top plug, and the jets on the top front under the bolt, and on the bottom half.

 

[juno pierrat]

How are the float levels set?

 

[cjbveteran]

I didn’t take the plugs out the carbs, I have the manual and it doesn’t say do that but the manual also doesn’t have my model carbs in it either. So today I will take them off again and remove the plugs and clean thoroughly.
The floats are parallel to the carb when upside down and when upright they both hang at 1.5 inches, which the manual says is correct but again they don’t have my carbs in the manual

 

[ahicks]

If you have compressed air available, use it to confirm what you think is clean IS actually clean by blowing through it.

 

[racerone]

The high speed metering jet is screwed into the very bottom of the float bowl.----Idle fuel goes through them as well I believe.----You have to remove the drain plug to remove / clean them properly.-----This jet is hidden and often overlooked !

 

[Crosbyman]

see pict... bottom jet in yellow also the low speed fuel flows to the top via a small side channel which must be clean includind the idle chamber under the round dime size plug.

don't remove it yet but at least clean all orifices
(check for crud including the small side channel leading up to the drip chamber .)

see old style carb drip chamber example. . modern carbs have fixed LS / HS jets instead of adjustable needles

use carb cleaner and blow dry .

if.. the float is cork do not apply carb cleaner to it

 

[cjbveteran]

So I have both carbs broke down and soaking in cleaner, I didn’t take the plugs out yet. In a hour or so I will clean and dry them and see if it solved the problem if not I will take them back off and remove the plugs and clean those areas then reinstall and see if that works.
Thank all of y’all so much for your advice, I will update this evening with the results.
If it doesn’t work then I’ll go get a compression tester and test the compression in the cylinders and post the results

 

[Crosbyman]

run some small monofilament line in each orifice to garantee proper cleaning of orifices. do not force metal wire so as not to damage any calibrated orifices ex: side channel leading to the top (look closely)

 

[cjbveteran]

Put it all back together after a long soak in cleaner, I did find in one carb that the small tube inside the bigger tube that goes to the bottom of the bowl was clogged.
It is idling with no problems and stays idling, although it may seem to be running a little rough. I will do a compression test tomorrow morning and see what it says.
Thank y’all so much for helping solve my issue

 

[Crosbyman]

run a cleaning product in your next tank

some like seafoam some don't ... Merc power tune or Evinrude engine cleaner may wake it up more.

thanks for your feedback

 

[oldboat1]

IMO, decarb products work about the same if application is the same. It might be useful to clean the tank separately from the carb (or start with a new tank and lines).

 

[Crosbyman]

IMO, decarb products work about the same if application is the same. It might be useful to clean the tank separately from the carb (or start with a new tank and lines).

yep... my comment was more directed or rather intendent for the engine and yes the tank needs to be cleaned on it's own !!! .