Mcculloch 4hp no start

[john8504]

No it’s definitely a mcculloch engine. They also made ted Williams, Sears, and a few other brands engines for a while.

[dockbuster1]

As Bill said it does have a syncronised throttle and spark advance . I am looking at page 19 fig 22 of the McCulloch 4 service training manual and it shows the spark advance lever so yours appears to be missing from the first picture. I have a running 4 and the point box does move when the throttle lever is moved good luck

[david-bartlett]

quote Callie30R:

As Bill said it does have a syncronised throttle and spark advance . I am looking at page 19 fig 22 of the McCulloch 4 service training manual and it shows the spark advance lever so yours appears to be missing from the first picture. I have a running 4 and the point box does move when the throttle lever is moved good luck

Lincoln.

His spark advance is visible in the pic but hard to see as it is the same color as the background. It is in the stop or slow position in the photo. May not be connected to the mag properly though.

What fun this little motor is bringing us!!!

[billw]

On the second tier of these posts, there are two pictures of your installed carb. In both pictures, the mag lever is in the stop position. In this position, the cam would be as you show, in relation to TDC. It would be firing after top dead center. Move the mag lever all the way to port and you should see the relationship to the TDC position change. The points will break near or before TDC. THAT’S where you want to try to start the motor.

If that lever doesn’t move, then it must be seized.

Long live American manufacturing!

[john8504]

Ok I’m an idiot. Yes it does move the points and adjust timing. I wish y’all could see the embarrassment on my face right now haha.

[john8504]

So here is what I have. Pic one is of points on cam when throttle off and engine at tdc. Picture Two is the throttle linkage itself. Picture three is of points on cam with throttle open to full and engine at tdc.

I have tried to spray some starter fluid and crank now with throttle open and still not results.

Let me know yalls thoughts.

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[retiredoz]

You might try it again without the choke ?

[billw]

No need to be embarrassed about the mag lever. It only points out how tough this forum can be sometimes, to solve things. Because we all can’t be in the room to help, it’s almost like when Johnny Carson used to dress up with a turban, hold an envelope to his head and try to predict what was inside it. Sometimes it is almost telepathic, because the written word is just not enough. If a picture is worth a thousand words, BEING there must be worth a million words.

If it still won’t go, my next move would be to pull the four screws behind the carb and have a look at the reed valves, to make sure they are not stuck open with debris. If the reeds are good, then I’d be squirting a a SMALL amount of gear oil into the cylinder to temporarily increase compression, and see if it will fart, then. By design, some engines will run great with 80 psi compression and others won’t even start. I don’t know about this particular model; although I BET 80 is good to go….(And I’d also recheck for a strong spark. Sometimes that can go away in the middle of things, because of a tiny piece of fuzz on the points or whatever. By the way, the spark should jump a measured 3/16" AT MINIMUM. 1/4" or more is the norm.)

Long live American manufacturing!

[joesnuffy]

Bills advice is dead on and should help find the issue. Please take of pics of the reed valve assembly. You have pretty much ruled out timing as your issue. You can put a bolt or screw or something into the spark plug boot or where it connects to plug to see how far you can get the spark to jump to see how far it will jump. I did read that those particular motors need a minimum of 90lbs psi compression to run but I also think 80 should be in the ballpark. Is your compression gauge accurate? Putting some gear oil into the cylinder like bill said will bump up your compression and if the motor hits a lick then you know it will need new rings. The man that taught at the night school I went to told a story of being a kid and having to put a small amount of oil into the spark plug hole to get his 2 stroke Jacobsen (i think jacobsen) to start since it didn’t have enough compression then he could mow. You could try that first since motor is still together along with how far the spark is jumping before taking reed valves off.

Once you try the oil trick to see if you can get it to hit re-check your compression with the gauge and let us know what psi is with the oil please.

Joe

ps the motor looks to be air cooled so the rings could in fact be worn out since the motor runs hotter than a water cooled engine and is mostly run in the summer months. I had a leaf blower that got like that once it would not start had fuel, spark, etc but not enough compression it needed a new ring or rings I had used it like 10 years at that point. If all else fails a person could pull the piston and carefully remove a ring and put it into cylinder and push it down like 1/2 inch using the piston and measure the gap in the rings using feeler gauges. Having said all that I still think 80psi should be good to go unless that number jumps dramatically once the oil is added thats why I would like to know what compression is after the oil is added.

[john8504]

I’ll try that this morning. If the rings are work, I have no idea where I’m going to find rings for this thing. Most parts are obsolete and there is no reference that I have found for what rings to put on it. If I could get rings, then yes I would be putting those on myself.

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