Not an antique, but I need some help.

[wiscoboater]

Fleetwin,
I had the idle adjustment screw in as far as it would go and everywhere in between. I will check butterfly for closure. I did have the high speed jet out. I unscrewed it with a small gun smithing screw driver. I did not have any difficulty removing or re installing it. Perhaps I should not have done that? The low speed needle looked fine when removed, and I replaced #29 with the new one from the kit. I have no idea how to sync the carb/timing.

[fleetwin]

OK, you had the jet out, and had no trouble doing it. I’m sure you did no damage provided your screwdriver was not scraping on the internal threads of the bowl. Be sure the jet is completely reinstalled and snug though, it can walk back out slightly and create a lean high speed condition if left loose.
I don’t think the lead shot comes with the carb kit, did you buy one separately? In any event, it looks like the lead shot goes right near the core plug, but you can not trust those diagrams and I don’t have a carb handy to look at. Did you remove the original lead shot? If not, and the lead shot fits loosely in the passage, you are placing it in the wrong spot. Some of those open holes in the carb body are vents, and meant to be open.
Now back to the carb synchronization. Let’s start with the choke linkage. The choke is linked to the carb butterfly so the butterfly will be cracked open when the choke is engaged. So, if that linkage is messed up, the butterfly will be cracked open when the choke is off. You could simply remove the link between the choke and butterfly to eliminate this possibility for now.
Next, have a look at the carb throttle roller up by the throttle cam. The cam should NOT be touching the roller at idle speeds (when the throttle is retarded below the two little marks on the cam). The throttle will be held open slightly if the cam is holding the roller open at idle speeds and the engine won’t idle. Finally, just because the cam is not touching the roller does not ensure the throttle plate is closed, which is why I wanted you to look at the throttle plate with the carb off to ensure it is closing and not binding. You could always temporarily remove the link between the butterfly and cam if you suspect something is binding in the linkage between the butterfly and cam.
You will find a long thin horizontal link between the throttle roller and mag plate linkage, this is the economizer linkage. If someone has grossly misadjusted this, it may be holding the butterfly open at idle speeds. You will see a little brass clamp with a set screw on the rod. Don’t mess with it unless it is misadjusted holding the throttle open, simply loosen the screw and move the clamp back towards the rear of the engine. Again, don’t mess with it if this is not an issue.
Finally, back to something I should have began with when talking about ignition problems, the spark plugs! Again, ignition problems can disguise themselves and sound like fuel problems. You might want to try a new pair of QL77JC4 plugs, even if the ones you have are new already, just cuz the plugs are new doesn’t mean they are any good.

[wiscoboater]

Thank you Fleetwin,
You have armed me with enough checks and adjustments to keep me busy for awhile. I’m bound and determined to get this motor running right. Thanks to all of you for your help and patience with me here, This ones a little harder then the 50’s era twins that I usually play around with. I will persevere and over come.

[wiscoboater]

Ok Fleetwin, heres what I have. The roller is tight to the cam at idle position and the butterfly is being held just slightly open. Not much, but a little bit. This is with the choke completely open. This is also with the roller about 1/2" to the idle side of the two marks on the cam. Up top the brass clamp on the rod is about 3/4 of an inch away from the nylon block on the linkage it slides through on the throttle arm. If I disconnect the rod from The butterfly to the roller the butterfly closes completely with out any binding. With the choke closed the butterfly is open quite a bit more.
This is not a tiller motor. It came off a pontoon with controls. The electric choke is not on the motor, just the manual pull choke. Something was messed up in the key switch every time I pushed it in to engage the electric choke it would pop the 20 amp fuse.

[johnyrude200]

A couple of things. The air gap tester is something I use too, but these newer motors should be producing at least a 1/2 inch bright blue spark. If you don’t gap it enough, you may not see any spark at all, or only see a weak spark. Believe it or not, if they aren’t gapped enough, you won’t see the spark get very hot. A tuned up CD ignition will jump that spark easily 3/4 inch. It’ll run at less, but you’re on borrowed time as the ignition system is on it’s way out.

[EDIT]Also make sure you are cranking it over fast enough when evaluating spark strength. If you have the right size socket and adapter, put a screw gun on the crank nut with the plugs out and use the screw gun to turn the motor over. Beats using a rope starter if you don’t have the controls for the electric starter. You can always wire up a bypass start switch through a solenoid, momentary on/off switch, and a positive lead off the solenoid and a negative ground off the motor to the negative terminal of the battery to use the electric starter. You’ll obviously need a positive lead from the battery going to the solenoid, too.[EDIT]

Check for good grounds on your coils and various leads; and make sure the fiber washers and star washers are all present on your ignition system and configured as they should be. Not having these set up as specified OEM, that will lead to problems and chasing ghosts. Check all your connections too between driver coil, sensor, power pack, and ignition coils. Corrosion interferes with things quite a bit.

A 105 compression on one of those 35’s isn’t horrible, but not too good, either. That could account for a stall at low idle (dropping compression).

If the thing is sneezing, refer to what everyone else has said, look for an air leak somewhere. If your rich/lean low speed knob is set a lot higher than it should, than that is a strong indicator that it’s running lean due to an air leak. The air silencer box (the big black plastic box) should say what the default settings are for the slow speed knob. If they’re gone, check a service manual to be sure.

If you richened up the low-speed adjustment needle and now it’s bogging down during acceleration, well now you know you’re running too rich. It should clear out and mid-range even if that’s set wrong. Sounds like an air leak, somewhere, to me. Again – refer to what everyone else has written – all good advice.

[wiscoboater]

Success!! I re adjusted all the linkages per Fleetwin’s guide lines, Checked my spark at 1/2 inch open air gap, hooked up the fuel and she’s ideling, NICELY!! Not one sneeze! It’s revving up much smoother as well. Smoother over all RPM ranges. THANK YOU EVERYONE! Now I need to get it sold so I have some walking around money for Tomahawk.

[johnyrude200]

Timing is a common issue with all of these motors, particularly newer ones with CD ignition. Follow those service manual calibration routines to a "T." It will save you a lot of headaches…ignition…then fuel system…then timing! Solves a big number of problems!

[1946zephyr]

May not be a ’57 Big Twin antique, but that motor is almost 40 years old. Still qualifies for good advice here 🙂

[wiscoboater]

I have to tell you guys, I have learned more from this thread then 3 years of puttering around in the garage blindly could have taught me. You guys are the best on the NET for knowledge and "been there, done that" hands on experience. Thank you again to all of you.

[fleetwin]

We are just glad it is solved. It’s always nice when posters take the time to answer questions completely and do their best to follow advice. I know it is very hard to understand advice given just by the written word.
You mention that the electric choke solenoid has been removed from the engine but the fuse pops everytime you push the key in to activate the missing electric choke. Where is the purple/white electric choke lead terminal now? Perhaps it is grounded somewhere on the block.
The 1977 35hp was not OMCs best effort, although later 35hp models were reliable. The 77 models had cooling issues, so it not a great engine to keep in your collection.

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