still fighting bogging 86 140 rude

[okam]

Like Brew2 still fighting bogging in midrange, idles, top end great. My question is the emulsion tubes in the center of the carbs, I have (2) carbs that the tubes appear to rising out of the carb body at differant heights. About a 1/16" of a inch. Is this normal? Or has someone over yhe years mixed the carb bodies. Thanks in advanced.

 

[okam]

Re: still fighting bogging 86 140 rude

Any thoughts anyone

 

[Brew2]

Re: still fighting bogging 86 140 rude

Hi Okam,

Still fighting the bog battle here too. Off for a week vacation tomorrow, so I'm hoping to find a solution while I"m there.

In my experience, the tubes are likely different heights because they have deteriorated at different speeds (ie. one has gotten shorter faster than another). The additives to gas eat away at those tubes. Mine were so brittle they literally crumbled as I touched them. After much searching and some help from Dhadley, I tracked down a marine engine shop in Port Charlotte, Florida that I could get replacements from. The tubes are just a pressure fit, so you can pull them out and insert the new ones.

I'm going to try using a toothpick to block the intermediate jet and see what happens. Not expecting a cure, but it will be interesting to see what happens. Theoritically it should flood and kill the engine. If the bog still persists I'm back to looking somewhere other than the carbs for the solution.

Good luck with yours. If I find and answer while I'm on vacation, I'll put a post up with your name on it.

Cheers.

Brew

 

[okam]

Re: still fighting bogging 86 140 rude

Thanks for responding brew2, I thought they might be but they still have a machined end. I think I'll try to even them out this weekend and hope for the best. I'll post back, have a great vacation.

 

[Dhadley]

Re: still fighting bogging 86 140 rude

Are you guys running with the airbox cover on or off? Is the cover stock or was the inner plate removed?

 

[shearpin]

Re: still fighting bogging 86 140 rude

this could be a crank case seal problem? At idle it could appear to be running fine but it wouldn't show it's face until there is a demand on the engine. would explain at midrang bog. at the upper rpm's the leaking seals wouldn't allow enough time to affect the lost cylinder.
check around the by- pass plates and up under the stator for signs of sweating, maybe and area on the engine sureface where and grim has been cleared away. To bad you couldn't pressure check the crank case.

 

[okam]

Re: still fighting bogging 86 140 rude

Dhadley, the air box is on with gasket, no mods to cowling or baffle.

shearpin This motoer had the same bog before a complete rebuild, motor has approx. 120 hrs since rebuild.

Thanks for the replies, any new thoughts are welcome.

 

[Cricket Too]

Re: still fighting bogging 86 140 rude

Actually having the same issue on a '76 115 (new powerhead in '97). Just started last weekend, runs fine at idle, trolling speed and top end is great, hitting 5800, but the mid range from about 2500 or so until about 4000 sounds a little rough for a couple of seconds and then it lets loose and flies right up to WOT.

Figured these carbs might have 3 different jets in them and a mid-range jet was getting clogged. Was gonna run a gallon of gas with seafom in it through the carbs and let it sit overnight, then change my fuel/water separator. Maybe I'll check my emulsion tubes while i'm in there, didn't know that could cause any issues. What excatly do the emulsion tubes do?

 

[wilde1j]

Re: still fighting bogging 86 140 rude

SeaFoam won't do squat ... it's for decarbonizing engine internals, not carb cleaning. In any case, the only way to clean a carb is disassembly, soak in carb cleaner and blow dry with compressed air, replacing any needed parts and all soft parts.

 

[Brew2]

Re: still fighting bogging 86 140 rude

Back from vacation....discovered a couple of things.

First, I found a set of jets in an old carb I had that were smaller than the stock #16 intermedidate jets. Don't know the exact size as there is no number stamped on them, but just by eyeballing them, you can tell they are slightly smaller than the #16s. Installed them and it did help the bog situation, although it didn't totally eliminate it.

Second, I discovered that the bog was almost entirely gone if I pumped up the fuel bulb and immediately took off. Once I returned to idle or stopped the engine for any period of time, the bog would return until I pumped up the bulb again. I assume that I've either got a air leak in the fuel line or a bad bulb. I replaced all the fuel lines and clamps last year, the fuel pump 2 years ago and the bulb 3 years ago. Guess I'll go get another bulb and recheck all the clamps for the umpteenth time and see if that changes anything.

Any other thoughts on why I would be losing the "prime" in the fuel line?

Thanks.

 

[bitsnpieces]

Re: still fighting bogging 86 140 rude

Back from vacation....discovered a couple of things.

First, I found a set of jets in an old carb I had that were smaller than the stock #16 intermedidate jets. Don't know the exact size as there is no number stamped on them, but just by eyeballing them, you can tell they are slightly smaller than the #16s. Installed them and it did help the bog situation, although it didn't totally eliminate it.

Second, I discovered that the bog was almost entirely gone if I pumped up the fuel bulb and immediately took off. Once I returned to idle or stopped the engine for any period of time, the bog would return until I pumped up the bulb again. I assume that I've either got a air leak in the fuel line or a bad bulb. I replaced all the fuel lines and clamps last year, the fuel pump 2 years ago and the bulb 3 years ago. Guess I'll go get another bulb and recheck all the clamps for the umpteenth time and see if that changes anything.

Any other thoughts on why I would be losing the "prime" in the fuel line?

Thanks.

the #16 orifice you mentioned is listed as an idle air bleed for a 120 horse ,the 140 has a #20 listed for intermediate,thought this might help