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Johnson 70 HP Carb issue

C

cfurlan

New member
The only way I can get it to start is by squirting premix into the carbs and then it starts fine. If I shut it off and let it sit longer than 5 minutes it won't start back up with out squirting it again. I replace fuel lines and clamps except for the really small ones on the carb, they appeared ok with no leaks. The motor runs great except for the starting problem, idles normal. I believe it is around a 1987-88. Any suggestions would be greatly appreciated, Thanks.
 
Sounds like you are not activating the fuel primer solenoid when starting OR the fuel primer solenoid is faulty.

(Proper Starting Method)
(J. Reeves)

NOTE: If your engine is equipped with an electric ckoke, substitute the words "Electric Choke" in place of "Primer Solenoid".

Cold Engine: Pump fuel primer bulb up hard. Increase throttle somewhat with whatever type control you might have. Turn key to start position. As engine cranks over, push in key to activate fuel primer solenoid. When engine fires/starts, release the key. Should engine start to die out, push key in (just a tap) as needed to activate primer solenoid in order to momentatily increase the fuel flow.

Warm engine: Pump fuel primer bulb up hard. Turn key to start position. When engine fires/starts, release the key. If engine does not fire/start within 6 revolutions, push in key to activate fuel primer solenoid as needed.
This is assuming that the engine is as it should be in all respects (Compression, Ignition, Carburetion, Fuel Supply, etc).

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay store at:
http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store

(Fuel Primer Solenoid Function)
(J. Reeves)

The RED lever...... The normal operating/running position is to have that red lever positioned over top of the solenoid and aimed at the other end of the solenoid, gently turned to its stop. This is the normal/automatic mode position. Pushing the key in opens the valve within the solenoid allowing fuel to pass thru it in order to prime and start the engine. Looking upon this solenoid as a electric choke results in a better understanding of it.

Having that red lever turned in the opposite direction, facing away from the solenoid, allows fuel to flow thru it to the crankcase area. One would only turn the red lever to this position in a case where the battery might go dead and the engine had to be started via the rope pull method. Look upon putting the red lever in this position as moving a choke lever on a choke equipped engine to the full closed position. Either one would supply fuel to the crankcase/engine for starting purposes BUT if left in that position while running would flood the engine.

The later model primer solenoids are equipped with a schrader valve, used for attaching a pressurized can of fogging oil etc, available at your local dealership with complete instructions.

Pumping the fuel primer bulb up hard fills the carburetor float chambers of course, but that process also applies fuel pressure to the primer solenoid.

The two small hoses leading from the primer solenoid branch off via tees to each fuel manifold section that would feed fuel to the individual cylinders.

Pushing the key in activates the primer solenoid to allow fuel to flow thru it to the intake manifold passageways. Cranking the engine over causes the fuel pump to engage which in turn sends fuel pulses to the primer solenoid via the 3/8" fuel hose.

Some engines incorporates the "Fast Start" feature which automatically advances the spark electronically so no advance of the throttle is required for starting. Engines that do not have the "Fast Start" feature will be required to have the throttle advanced slightly.

Starting procedure: pump fuel bulb up hard, crank engine and push the key in at the same time. When the engine fires/starts, release the key so that it falls back to the run position.

Bottom line..... Look upon the primer solenoid as an electric choke.


Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay store at:
http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store
 
Last edited:
Hey thanks a lot, that is exactly what I am not doing. I will try this tomorrow. I know I have a spare solenoid too from a parts engine. Thanks
 
Well that fixed that problem! BUT, I put it out on the water today and every time I give it some power it bogs down and downs in forward and reverse. It runs fine when lifting the idle lever though. Any suggestions?
 
I do not know because I just got it, I think the guy said 3-4 years. It does run normal with muffs on in the driveway too. Thanks
 
Usually caused by the fuel turning to "varnish" with age, and blocking the jets, especially any located in the bottom of the carb.
 
As above, clogged jets. The main high speed jets are located in the bottom center portion of the float chambers.
 
Well I tore the carbs apart and cleaned them. I did not see anything unusual in them and they really weren't too dirty. I put them back on and started the engine at a slight angle without the airbox on. When its running, fuel drains out of the carbs on the airbox side. Would that be a sign that the floats are stuck, bad needles, or is this normal. Thanks
 
Did you manually clean the high speed jets?

(Carburetor Float Setting)
(J. Reeves)

With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (just ever so slightly off level) than the other end. And when viewed from the end, make sure it is not cocked.
Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay store at:

http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store
 
Well I fully rebuilt the carbs and that seemed to fix it. Now I just need to adjust the cable controls a little to get it perfect. Thanks for all your help and I will let you know if I have any other issues with it. I'll mess with it some more tomorrow. Thanks again.
 
Well I got it out this morning and it seems to starve for fuel when in gear. If I squirt it with the choke and in gear it takes right off for about 5 seconds and then I have to squirt it again. It runs fine in neutral with the idle up a little but when I lower the idle, it wants to die. Could this be the fuel pump? The ball on the fuel line stays hard the whole time too. Thanks
 
When this happens, have someone pump the fuel primer bulb, acting as a manual fuel pump. If this cures the problem, either the fuel pump is faulty OR a air/fuel eak exists somewhere.

You didn't answer my question..... Did you manually clean the high speed jets? If you did not, I would suspect that therein lies your problem.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay store at:

http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store
 
behind the 7/16 carb drain screw on front,there is ur HIGH SPEED JETS....unless u ck them w/a light,i bet one or both are not spotless.....as they need to be.!
 
i soak them,in carb cleaner solution,unless,they are plsatic bodied..then i rinse them w/water,thoroughly,..then blow dry,and before assembly,i take a jet screwdriver,and make sure they are snugged,and ck w/a flashlite,...each and every carb.look into every orifice u can to see any obstruction.
 
Well I checked those and made sure they were clean, then I just rebuilt the fuel pump too today and that didn't help either. There is fuel in the carb bowls. It barely runs in nuetral now unless I up the idle some or choke it with the solenoid. I don't know what else to do because I've fixed or replaced everything dealing with the fuel system.
 
The high speed jets...... I remove them, then clean them out carefully with a piece of single strand steel wire, commonly called mechanics wire.
 
a 'jet' screwdriver---or some such mfg item,....the prob is,...most,will break off that area,...then,u have a bigger prob than u started with....plastic bodied carbs,as much as i hate them,jets always unscrew,...others,...usually are stuck,..
 
Now I'm worried about even trying to remove them. I guess I'll try to soak the bowls first to see if that will work. Thanks
 
Well I cleaned them again today and let them soak. I also removed all jets with no problems and let them soak as well. I blew everything with air before putting it back together and then put it back on. It started fine but once I got away from the dock it started to die again. I removed the fuel filter to make sure it was not clogged or leaking too. The ball still holds prime and squeezing it does not help. After I got back in it would not start at all, even when trying to choke it. I think its worst than before now. Thanks Chris
 
Past experience, if any discrepancy in gaskets / o-rings, seals, ect. change them now (rebuild kit) Ethanol can really do some weird things sitting in your carb for long periods. Some cases a ruff yellow/green haze coats everything and inside of jets,, Air may pass thru but fluid maybe slightly restricted. Sounds like its trying.. But starving... Do yourself a favor and piece of mind, order a kit.
Remember: If its going to happen, it will happen out there! (quote by Captain Ron)
 
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