Update on my 1985 140hp Johnson - mist coming out the carbs

[Bobby D.]

I posted last week about the atomizing coming out my four carbs. The mechanic indicated that the powerpack was defective and that the timing was way off. I could understand the bad powerpack but I don't know how the timing got way out of time. Today I went fishing for the first time since the repair and the motor went well at speeds up to 3000rpm and then I noticed the temp had gone into the overheat range. I went back to the dock at 1200rpm and the temp was okay. Can someone tell me why the timing should have moved as indicated by the mechanic and why it overheat at high speed and not at low speed. Also, can I use an automotive timing light or do I have to get a two cycle timing light or is that a silly question?

 

[walleyehed]

Re: Update on my 1985 140hp Johnson - mist coming out the carbs

Automotive timing light is fine.....as for over-temp, I have to wonder where the timing is actually set to, although I'm not sure it would show-up that quick.<br /> the mist from the carbs is usually normal, as they do spit a little back fwd.<br /> Check the timing with the plugs removed, and either spark testers, or the plugs in the boots and grounded. Disconect the throttle linkage and hold throttle wide open while checking the timing. It should be about 2 degrees retarded of spec by this method..

 

[Dhadley]

Re: Update on my 1985 140hp Johnson - mist coming out the carbs

You arent running that motor with the air silencer off are you?

 

[Bobby D.]

Re: Update on my 1985 140hp Johnson - mist coming out the carbs

Dhadley the air silencer is that the cover over the four carbs? If it is, it is in place.<br />Walleye, Can I lift the throttle lever above the key switch all the way up? Would that be the same as disconnecting the throttle linkage? You said that the timing should be 2 degrees retarded. What should the actual reading be for this motor using your method and less the 2 degrees. I believe the manual sez 8 degrees at idle.

 

[walleyehed]

Re: Update on my 1985 140hp Johnson - mist coming out the carbs

Idle timing won't be a factor except to set idle speed. You want to disconnect throttle linkage and hold the throttle cam WIDE OPEN to check the timing full advance, which should be on a sticker ontop of the carb silencer. I'm not sure of the timing for that engine, but I don't think it should show above 25-26 degs BTDC. If you have a manual, it will state max timing advance, but the method I'm talking about here, you will want about 2 degs. retarded of the stated max timing advance. If max timing is 28degs., you should see about 26 degs.......<br />Dhadley may have the proper timing figure for your engine as well...... <br /> I guess I should state this is a 2 person job...one needs to be turning the engine over with the switch-just as if starting, while you hold the throttle and run the timing light........BE CAREFUL!!!

 

[backdraft]

Re: Update on my 1985 140hp Johnson - mist coming out the carbs

Dude, the misting coming out of the carbs is normal. As the reed valves [petals ] close , the atmospheric pressure just before the reeds go from a negative pressure ,to a virtual stop ,then to a very miniscule positive pressure. This air along with the fuel that was drawn from the carb backs up, spitting out the venturi . This normally only occurs at low speed ,as at high speed the velocity and increased volume doesn't let this occur. If the timing is totally too advanced , the intake port in the cylinder is not covered by the piston allowing the gases from the combustion to pass back into the crankcase . Normally the reeds will not let these gases blow out the carb, but if they do when the pressure is too great, damage is done to the reeds and the motor ceases to run properly. This is the normal operation of such a system and there are exceptions to everything. nevjb

 

[Bobby D.]

Re: Update on my 1985 140hp Johnson - mist coming out the carbs

Walleye, The cover has 22 degrees BTC on a decal.The mechanic said that an automotive timing light would not work on a two cycle engine.<br />Nev, thanks for the explaination.

 

[walleyehed]

Re: Update on my 1985 140hp Johnson - mist coming out the carbs

Dude, I could be an idot here, but I use an automotive timing light on mine......a sparkplug wire, is a sparkplug wire, and they both are firing the same type of plugs.<br /> I get the impresion he doesn't WANT you to know where your timing is.<br /> Anyone, please jump in....am I wrong on the timing light???????? <br />Oh yea, if the max timing is 22 degs., set it at 20 degs..........with the automotive timing light.

 

[G DANE]

Re: Update on my 1985 140hp Johnson - mist coming out the carbs

Dude and walleyehed <br /><br />I never knew there was a 2stroke timing light ?? I never owned one. <br /><br />Spark is spark, advance is advance. However the difference in rpms from crancking speed to wot will add 4 deg extra ignition advance, not 2. Do the test by jumping starter with plugs out and grounded - you dont want it to start, and plugs left in air can damage cdi box.

 

[walleyehed]

Re: Update on my 1985 140hp Johnson - mist coming out the carbs

G DANE, you're correct on the 4 degs. I'm used to going back 2 degs. because of our altitude-we run 2 or 3degs. advanced.......thanks for clearing that part up-I'd hate for someone to screw up on my account..........

 

[Dhadley]

Re: Update on my 1985 140hp Johnson - mist coming out the carbs

22 degrees is correct on the 1985 V4 looper. 1986 and newer were different.<br /><br />For years I have heard that you cannot use a "4 cycle" light. Seems to work OK for us.<br /><br />Good luck!

 

[Bobby D.]

Re: Update on my 1985 140hp Johnson - mist coming out the carbs

G DANE, Just a clarification. You said 4 degrees does that mean it should be 26 degrees or should it be 18 degrees? Thanks guys.

 

[walleyehed]

Re: Update on my 1985 140hp Johnson - mist coming out the carbs

18 degs. is the max you should see....remember this is a "before top dead center-compression", so the closer to TDC, the lower the number will be (more retarded). Good luck!

 

[backdraft]

Re: Update on my 1985 140hp Johnson - mist coming out the carbs

Most all timing lights work off induction. It does't know if it's two or four stroke. An electrical magnetic current surrounds a wire as electricity is pushed through it on each pulse. Some 4 strokes fire at both top and bottom . There's a lot more on this , but on a 2 stroke, forget it. nevjb