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Johnson 4hp

Just turn the needle out counterclockwise 1/4 turn and see if it idles any better? I found with these small displacement engines it is best to set the points using the special tool or use a timing light. Connect the light to any battery and clip it on a plug wire. Then shine the light at the two marks on the side of the points plate. The single mark on the flywheel must be inbetween the two marks on the plate. Never had much luck cleaning the points they usually foul out after a short while. Install some new points and condensers then adjust the points according to the timing marks. It is time consuming but well worth the effort.
 
If it runs nice from just over half throttle and up and is hard to start. Could it be the ignition system. Ie coil points etc
 
LumleyRick said:
If it runs nice from just over half throttle and up and is hard to start. Could it be the ignition system. Ie coil points etc
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I suspect the low speed fuel circuit in the carb is plugged-up. You might get by by adding some Chevron Techron fuel system cleaner to a few tanks of gas.

Bill
 
I just took the flywheel off and the points are opening way more than .20. Also found the top crank seal has a small leak. Wondering how much compression can b lost from small leak.
 
Have you tried using the choke when you want to run it full throttle? If it works better with the choke on then I'd say you need to clean the carb and install a carb kit.
 
The choke was killing it. Have the carb off so may as well do the kit and new gaskets. I am surprised it started with the points that far off. Is the top bearing and seal together or seperate.
 
Actually it loses the fuel precharge in the crankcase as the piston goes down it builds up pressure and when the piston reaches bottom if forces the air fuel mix into the cylinder. It will also keep the fuel pump from working if it loses the precharge pulse.
 
LumleyRick said:
I just took the flywheel off and the points are opening way more than .20. Also found the top crank seal has a small leak. Wondering how much compression can b lost from small leak.
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From my experience an induction leak (crankcase leak) will cause your engine to run poorly or not at all. I had a Mercury Mark 20 that was a nice running engine. Then it was stored in a very damp basement for about 10 years. I would not start or even "pop" when it was turned over. The problem was that the upper crankshaft sealing surface had rusted and the neoprene seal could seal no more. The engine was junk and required a new crankshaft - it never ran again. You have no choice but to replace that crankshaft seal. Until you do you'll have nothing but headaches.

Bill
 
You can pop the seal out with a couple sheet metal screws jut screw in a couple threads and grab the screw with a pair of vice grips and tap up with a wrench on the grips. Once you get the new seal find a pipe the same size andput a light bead of loctite on the outer edge of the seal and gently tap it in. Also with a q tip put a little oil on the crank so the seal does not run dry on the initial spin up.
 
kimcrwbr1 said:
You can pop the seal out with a couple sheet metal screws jut screw in a couple threads and grab the screw with a pair of vice grips and tap up with a wrench on the grips. Once you get the new seal find a pipe the same size andput a light bead of loctite on the outer edge of the seal and gently tap it in. Also with a q tip put a little oil on the crank so the seal does not run dry on the initial spin up.
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Excellent suggestion! I find that I can usually find the right size socket from a wrench set to fit the metal portion of the seal. I usually tap the socket with a plastic mallet and I like Permatex High Tack gasket sealer in lieu of Locktite. You're right not to try to pry the seal out and run the risk of damaging the crankcase.

Bill
 
That would need to be a deep socket if possible i have used a large punch also just take your time and work it down slow and even. Ifthere is agrrove in the shaft where the old seal rode dont press it all the way in 1/32 inch so it seals the smooth part of the shaft.
 
Points are pretty cheap. You've already got it torn apart so why not put in new ones and be done with it?
 
They can be a pain sometimes find out how far they move when you do the final tightening then go back with the feeler and set the that amount smaller and then chec it after tightening. You may be able to hold the gap with one screwdriver and tighten with another. It may help to get new star washers also.
 
What color are the coils? If the coating is cracked just replace them as a set. If you replace the coils you need to pull the mag plate and take some pics of the bottom. The wires need to be screwed into the coil and then slide the boot up tight then install the coil. The plate has machinedbosses you must put the outer edge of the laminate up flush with the boss it is sitting on. Be sure and torque the flywheel to spec before starting it.
 
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