Johnson 1984 70 HP

[catman977]

The Purge Ports can't be used by a manometer? There's vacuum there. Are the air screws adjusted by ear, or is there a Factory set way, to balance the 3, after teardown and reassemble? Just trying to do it right. Thanks for the help. I'm waiting on carb kits, in the meantime I'm rebuilding the water pump. Also using too much Sea foam in the fuel ,eats up Fuel Pump diaphragms. Done that before I swapped out the coils and master ingnition module. It's easy to blame top end preformance on the fuel system when the Fire isn't there. I will post how everything turns out after the redo. Thanks again

 

[catman977]

Hi Everyone Just an update on my Evinrude 70 1990 outboard repair. I replaced the 3 coils, and the main ignition Module, with OEM new. I rebuild all 3 Carbs with new Floats included. I got it started on a garden hose and adjusted the three carbs for pretty fair idle. I ran it on the Osage river and entered the Missouri River about 8 miles down. The Motor ran great and never missed a lick until, I headed back home. It started cutting back like it was running ,
on only two and sometimes three cylinders. I got it loaded and back to the shop. I forgot to say, I installed new Plugs the OEM champion, I suspecting these may be causing the problem. I had NGK in before, and today going to reinstall new ones, plus some of the easy stuff like another new squeeze bulb and line.. Anyone know what I may be overlooking? Thanks Happy Boating everyone

 

[juno pierrat]

believe some were in post you said you had a manual, ohms test on timer base

 

[catman977]

Don't recall test on timer Base. ?? Today I swapped the Champion Plugs with new NGK's, also I installed a new fuel line plus Filter, and did a test with Garden Hose again. So far it runs ok and Idles fair, Headed back to the river in the AM for another long range test up river, I will post how it preforms, hopefully I can burn a full Tank of fuel with no issues. I plan to take this boat and motor down the Missouri river from Omaha to Jefferson City next year, a little over 400 miles. I've done this once many years ago, and wanting to do this one more time. It's an experience of a life time, I need to make this motor work.

Thanks Everyone

 

[catman977]

Hi All I need to ask, How important is the Length of the small fuel line hoses between the Carburetor's on my 3 Cylinder Evinrude 70 hp. and the TEE'S? I Pulled them all off, and installed a Fuel Block, with 4 Ports out, and one in, for the fuel pump feed. I used transparent fuel lines to each carb and the purge solenoid. Could this be the reason I can't get the Idle smooth? I checked the replacement hoses and Tee's, and they are custom cut to length. I thought it was an engineering, cheap way to feed the carbs, but if I need to replace my Fuel Block with the original Tee's and hoses for good Idle I will.
Thanks For any help.

 

[racerone]

Explain what you mean by the------purge solenoid -----On your motor.----I do not believe your fuel block modification has anything to do with how your motor runs now..

 

[catman977]

Hi racerone Yes my 1990 70 HP (E70TLESB) Has a Primer Solenoid or Fuel Purge and requires one fuel input hose, I'm still not getting a smooth Idle. Is there a you tube, by the OMC people,on sequence in tuning, or balancing the three carbs? I watched the one they have, for the Linkage and timing procedure, which was great for initial setup, but vague on Carbs. I took my boat out for a couple of days, this weekend on the river, and noticed that my battery wasn't taking it's usual charge, via a digital dash volt meter. So I pulled the battery, and found it's time to change out for a new one. This may have something to do with total performance, and hopefully idle problems. I'll post what I find. Thanks for your input racerone.

 

[racerone]

The primer solenoid is an electric valve.-----It opens when you push the key in while cranking .----It then sprays fuel into the carburetor throat for near instant starting.----A vast improvement over choke plates.----Not sure why you would call it a " fuel purge " item -.------The ignition system on your motor does NOT use 12 volts from the battery to make spark !!

 

[catman977]

Yes racerone I understand the fuel primer and it's function. My problem seems to keep coming up, after I make a run up river. For about an hour or so, the motor runs fine and full throttle. I pull in and Fish for an hour or so, then head back down river. The motor then seems to start missing, and begins to run rough. I pulled it home and pulled the cover off, and I noticed the bottom 2 cylinders behind the Carburetors is wet looking, like maybe fuel leak.. I'm thinking maybe an intake leak. I'm going to clean and dry this up and run it on the hose to see if I can locate where its coming from. I know a vacuum leak drives a 4 cycle mechanic nuts. Do you have any thoughts on this? This would have a lot to do with my not so smooth Idle too. ???? Thanks for all your good input.

 

[catman977]

Today I pulled the Air Box off the carbs, and also the starter. Checked everything for leaks, and found a little fuel leak at the top carburetor in line. I replaced all the lines and decided to check my Idle and see if anymore leaks occur . Started it up with the hose again. It still didn't seem perfectly smooth Idle, I tweeked the Idle screws, and then I would check if it would rev a bit. It would cough and spit back through the prop exhaust, and act like it was trying to drop a cylinder. I have a new fuel pump that should be here tomorrow, I'll go ahead and install it but doubt if that will help. Getting discouraged a little.

 

[GA_Boater]

I have a Similar Motor that I'm going to do a 3 Carb Rebuild. It's a 1990 70 Hp Evinrude Model E70TLES8.
Each carb has an air adjustment screw. Is there a set amount of turns to pre adjust each of these after reassemble,
and can they be synched or balanced with a Manometer for smooth Idle. Thanks for all responders.

You are hijacking this thread. Start your own thread!

 

[catman977]

I found the Problem with my Motor not running good ,after going out for the day ,then limping Home. The Fuel Pump had a vacuum leak, because it was designed to bolt up solid to a manifold, that has a fixed port, my motor was at one time a VRO, the previous owner, told me that it malfunction, and the Power head had to be rebuilt, and converted to a 50-1 mix. it has a hose barb in the side of the manifold for it to hook to a standard Pump. The Pump I had on it, had the three barbs for Fuel in, Fuel out to Carbs and one for Manifold Vacuum. the Problem was the rear hole, is usually plugged solid so it can't leak, my pump had it open and also the hose barb too. It ran good when my 18 Gallon tank, which is above the motor on the pontoon boat. I guess it was kinda in a siphoned mode, until the fuel was about half full. then it started running rough. That's why there was oily film in the bottom two cylinders on the manifolds, blowing out that little hole in the back of the pump.
I have it in a Tank now to do my Carb adjustments, put on the air box and back out on the river for another real test. Thanks Everyone for all your good input. Happy Boating.