1976 135 just known for poor idle?

[derek4325]

So i have a 1975 135 johnson that idles a little higher than I want it to. It runs for a short while on low idle (just enough time to put it in gear without slamming in) but stalls if i dont act fast enough and rev it back up. That being said. Last year i went through and replaced everything ignition related except for the stator which i know is good. Took the carbs off and apart. Didn't rebuild them however I carefully looked them over and cleaned them. I did not remove the fixed needles because.. well.. they're fixed and i dont want to mess with them. So i have heard that these engines are just simply known for being poor idlers. Is that true? I also timed it to the best of my ability usung the joe reeves method. Could it be the brand of oil im using? I know I'll get a lot of eye rolls for saying this but i use walmart brand tc w3 in all my outboards and never had a problem, including my my 59 evinrude lark which runs and idles like a top. So yeah sorry for rambling on lol. Inputs? Thanks, Derek

 

[jimmbo]

Well if the carbs aren't in sync with each other, and also in sync with the ignition advance, it will never idle right. You took the carbs off, so that would disturb both of the syncs. If I remember right that engine does not have an adjustable idle mixture, so float height is even more critical, as is cleanliness of the carbs fuel circuits, and carb/intake gasket sealing. When cleaning a carb, all the nooks and crannies where gum and varnish can accumulate must be cleaned out, that means removal of jets, and the round disks that provide access to the fuel circuits. However before you go and spend money on carb kits and cleaners you should check the compression, if you haven't already. If you have, what are the numbers?

 

[derek4325]

Well if the carbs aren't in sync with each other, and also in sync with the ignition advance, it will never idle right. You took the carbs off, so that would disturb both of the syncs. If I remember right that engine does not have an adjustable idle mixture, so float height is even more critical, as is cleanliness of the carbs fuel circuits, and carb/intake gasket sealing. When cleaning a carb, all the nooks and crannies where gum and varnish can accumulate must be cleaned out, that means removal of jets, and the round disks that provide access to the fuel circuits. However before you go and spend money on carb kits and cleaners you should check the compression, if you haven't already. If you have, what are the numbers?

I have 125lbs in all 4 cylinders. I did stnc the carbs back together via the service manual. Im just afraid to pull the high and low speed jets in fear that i wont get them EXACTLY where they're supposed to be from the factory. I sprayed a generous amount of carb cleaner in the areas where the needles are, just did not remove them. Motor runs great at all the mid range and full speeds and it doesn't even idle TERRIBLE, i can live with it its just a little higher than what i would want it to. Thanks for the reply

 

[racerone]

They idle very nicely when in good condition !!-----The high and low speed jets are a brass screw with a calibrated hole in them .--They are NOT NEEDLES !!--------That is how they regulate the fuel.-----You install them by gently screwing them in till seated and they will then work EXACTLY as installed at the factory.-----Are you sure compression was exactly 125 on all cylinders ?----You might want to remove bypass covers to inspect pistons and rings.----These motors had a habit of breaking the top ring.----Some will argue about doing that simple inspection.

 

[derek4325]

They idle very nicely when in good condition !!-----The high and low speed jets are a brass screw with a calibrated hole in them .--They are NOT NEEDLES !!--------That is how they regulate the fuel.-----You install them by gently screwing them in till seated and they will then work EXACTLY as installed at the factory.-----Are you sure compression was exactly 125 on all cylinders ?----You might want to remove bypass covers to inspect pistons and rings.----These motors had a habit of breaking the top ring.----Some will argue about doing that simple inspection.

Yeah I'm sure they were all 125psi as of last year. And they are all the same psi plus or minus a pound or 2. And OHHHHH..... i didn't realize that they are just screws and not needles lol. Makes sense. I don't have much experience with fixed jet carbs. Just a little back history, when u bought this at an auction a couple years ago this engine haddent been run in whi knows how long. I ran it all last season and it seemed to do better and better. Thanks for the reply!

 

[Lightwin 3]

Pulling the heads is not that hard, or expensive, and will give you piece of mind as to cylinder condition. While you're at it, you can inpect/replace the thermostat and poppets. Also make sure the water deflectors are in place under the head covers.

The 135 didn't idle as smoothly (IMHO) as the lower HP V-4's but it shouldn't be acting as it is.

If you're going to go back into the carbs, get the kits and do as suggested above. You've got to get into and clean every little crevice and opening.

 

[F_R]

I wonder if you are expecting too much (???). I don't remember off hand what the idle speed is supposed to be, but probably something like 650 RPM in gear. That might translate to something like 8-900 in neutral or thereabouts. Your manual should give the in-gear spec. Then whatever it is in neutral is what it is.

 

[oldboat1]

You know the jet (or "orifice") is under the plug, though, right? After removing the outer plug, you CAN remove the jet but they are brass and easily damaged. I recommend taking the carbs apart and soaking tops and bottoms -- plugs off, but jets in place. After soaking, blow out all openings with carb spray using the plastic nozzle, and use soft wire or a piece of mono to clean out the jets.

 

[derek4325]

Thanks for the input everyone! I had it out the other day and this time it idled okay but when i gave it full throttle it wanted to die on me. Took a long time for it to finally give in and open up and then it ran beautiful. Who knows... maybe i didnt time it right? It's hard for me to do because the only truely right way to time it is on the water