35hp Johnson Bogging Down and Foot Oil Black

SouthCarolina1

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With the carburetor upside down the float should be level.----No need for any fancy adjusting.=====Pinch the primer discharge line closed when motor is running as a test.---What does a compression test show on this motor.

Ok so you are saying by pinching the primer discharge line closed while the motor is running and see if I notice any changes in the motor? Will this determine if the primer pump is leaking by? Will this work with the motor on a boot or should it be in the water under load?

When this all began I checked the compression and both cylinders had 125 PSI +/-2.
 

racerone

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Yes , when you pinch that line you are checking to see if the primer is leaking / flooding the motor.----And have you checked the size of the high speed jet that is screwed into the carburetor bowl, yes or no ?
 

SouthCarolina1

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I tried unscrewing the high speed jet but the insert for a flat head is broken (PO did that)... so if everything else fails I will drill it out the high speed jet slightly wider. It is so small I don't see how I could drill out completely to remove it without damaging the threads. At that point I would have to buy a new float chamber.
 

racerone

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If you are not sure of the high speed jet size you have to do something.----Even if it includes finding another float chamber.----Easy to find in my workshop !.
 

oldboat1

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not attempting to change focus, but it looks like fuel quality remains on the table (water in the tank) -- would affect both starting and running.


For testing, would need to draw from the bottom of the tank (primer bulb should draw from the bottom, so could just pump out some fuel for testing that way). Standard test is to put it in a glass jar and let it settle out. Fuel will settle on top of any water. Hull motion will cause the water to slosh around, and could give you changes in operation when underway. Permanent tanks are more of a problem than portables.

(mid-80s would use a 50:1 mix, btw.)
 
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SouthCarolina1

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I ONLY ever use ethanol free gas. I have also poured out the gas tank and cleaned the inside twice. But when I say primer pump I am not referring to the primer bulb. My carb. has a primer pump instead of a choke valve.
 

racerone

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Simple fix is to run a # 7 drill in there.----Then a 1/4-NC tap to clean out the remains of the jet.----Install a new jet.
 

SouthCarolina1

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Ok so I just ordered the proper high speed jet, 328525 — ORIFICE PLUG, #38D - 35, 40 ELECT MODELS. I plan on heating the carb chamber up for a solid 15 minutes with a torch and then attempt getting it out with the ez out. And rebuilding the carb, and checking the throttle setting. I'll report back once I have tested the boat out again.
 

oldrem

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Ok so I just ordered the proper high speed jet, 328525 — ORIFICE PLUG, #38D - 35, 40 ELECT MODELS. I plan on heating the carb chamber up for a solid 15 minutes with a torch and then attempt getting it out with the ez out. And rebuilding the carb, and checking the throttle setting. I'll report back once I have tested the boat out again.

Careful with that torch. A standard propane torch can reach over 2200 deg F, while cast aluminum melts around 1100 degrees.
 

SouthCarolina1

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Well OK then! I am used to backing off a rusty bolt on a tractor by heating that steel up until it's red hot! I knew aluminum has a low melting point compared to steel, I've just never had to torch a brass fitting in aluminum. My past experience with aluminum is that with enough elbow grease it comes loose.
 

oldboat1

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concave side of the float faces "up" when you have the top inverted (tab is down toward the float needle seat). I usually adjust, if needed, by bending the arm slightly. I just eyeball them to level -- some raise the outside end slightly above level, presumably to help insure float valve closing. Continue to think there is a simple fix for you issues, but it does sound like a PO did a job on the h.s. jet.

The .038 jet is the right one for the carb you mention (0431879). That carb was used on the '86 Johnson J35AELCDE (maybe others). But model J35RCDM (and E35RCDM -- the motor you cross reference) used carb 0439389 with h.s. orifice .063 (63D).

I gather you are replacing the oversized carb that PO's shop had installed, or at least the h.s. jet, but there are a couple of different carbs used on '86 Johnson 35s (with different jetting). I'm a little confused about what your are doing (i.e., what carb you are using, Did the military specs identify a specific Johnson/OMC model corresponding to the military motor?) That plastic top in your carb pic wasn't used until about '92/'93, so guess I'm just not sure what you have there -- or what you need.
 

SouthCarolina1

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Ok so I was able to get the high speed jet out. Engraved was “55D”. I installed the jet “38D” and then performed another carb rebuild. Now the motor runs WORSE?! Prior to switching jets the motor would just bog down and stay around 2500 rpms. After switching the jets, when I sightly throttle the motor it dies. If I covered 75% of the carb air intake only then was I able to throttle the motor without it dying. Even then I could barely get the rpms over 2000. I am considering taking the 55D jet and drilling the orifice to slightly larger opening. Any other suggestions?
 

racerone

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Where did you come up with the 38D jet ????-----The parts book shows a 63D for a 1986 model 35 hp.-----What other trouble shooting has been done on this motor ??------Carburetor issues / " problems " usually turn out to be something else !
 
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SouthCarolina1

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Dang I posted the part I bought! Why didn’t anybody say something? Well I ordered part # 328544 the 63D. I’ll let you know how that goes.
 

oldboat1

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Think you were advised 63D would be correct for the motor you referenced:

"September 22nd, 2017, 04:03 PM
Hey! I just got a 1986 35HP Johnson. The motor is a MARS motor. I have not been able to figure out the equivalent Johnson model number, might be E35RCDM? The motor runs great and is easy to start." [italics mine]


But model J35RCDM (and E35RCDM -- the motor you cross reference) used carb 0439389 with h.s. orifice .063 (63D).
 

geoffwga1

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Haven't seen anyone mention it but go check the packing on your slow running needle.
 

SouthCarolina1

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Well fellas the 63D high speed jet was it. Installed it and took the boat out for a spin. Had to do some tuning but the motor is now running like a top. Thanks for everyone's help, I really appreciate it.
 
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