Mcculloch 4hp no start

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retiredoz
Posts: 453
Joined: Mon Mar 09, 2015 12:22 pm

Re: Mcculloch 4hp no start

Postby retiredoz » Fri Apr 06, 2018 9:49 pm

The older style Tecumseh with two adjustment needles is pretty close. The pre-'60 3.6 Scotts used a Tillotsen, and I never could figure why they stopped. MD12A for a while, MD35A, there may be others that might work.
If you have an old yard equipment repair shop within reach, they may still have Walbro LMGs, I'm pretty sure they had widespread application..

John8504
Posts: 35
Joined: Mon Apr 02, 2018 9:39 pm

Re: Mcculloch 4hp no start

Postby John8504 » Tue Apr 10, 2018 3:46 pm

So I ended up finding a carb for a 70 3.5 mcculloch on eBay and I'm just waiting for it to arrive and see what happens with that. I hope it works.

retiredoz
Posts: 453
Joined: Mon Mar 09, 2015 12:22 pm

Re: Mcculloch 4hp no start

Postby retiredoz » Tue Apr 10, 2018 8:49 pm

Some Ebayers know not what they have. McCulloch officially spit the bit in '69, and to my knowledge never produced a 3.5. But whatever it is may be close enough..

John8504
Posts: 35
Joined: Mon Apr 02, 2018 9:39 pm

Re: Mcculloch 4hp no start

Postby John8504 » Wed Apr 11, 2018 12:25 pm

I looked at it and they might have the year wrong but it looks identical to the once that should be on mine. It'll be here Friday, so we shall see

John8504
Posts: 35
Joined: Mon Apr 02, 2018 9:39 pm

Re: Mcculloch 4hp no start

Postby John8504 » Fri Apr 13, 2018 12:08 am

This is the one I purchased.
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John8504
Posts: 35
Joined: Mon Apr 02, 2018 9:39 pm

Re: Mcculloch 4hp no start

Postby John8504 » Fri Apr 13, 2018 10:47 pm

So I put carb on and adjusted needles. Still no start. I took crank cover off to check the reeds and the reed stops. They seems to be in good shape. Made new gaskets and out back together. Still same results.

At a loss right now.
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retiredoz
Posts: 453
Joined: Mon Mar 09, 2015 12:22 pm

Re: Mcculloch 4hp no start

Postby retiredoz » Sat Apr 14, 2018 2:31 am

Are you sure you have fuel flow ? that little eco-unfriendly little button on the bowl is a drain, push it and see if it leaks. If it does, you're OK. Get yourself a can of spray starter fluid, and give it a short burst in the carb throat, and crank. If still nada, I'd check compression.
You could also just try cranking with the choke closed ?

John8504
Posts: 35
Joined: Mon Apr 02, 2018 9:39 pm

Re: Mcculloch 4hp no start

Postby John8504 » Sat Apr 14, 2018 7:30 pm

Yeah I've done everything I know how. I rebuild the mcculloch chainsaws as a hobby and I have 4. So I know that the engine is a modified chainsaw. I have that going for me. The carb is a glorified lawn mower carb. When I got the carb in, I took it all apart to see about cleaning and it was perfectly clean. The drain on bottom does its job and I have fuel coming out. (Waiting on a carb kit for it since the drain gasket is bad and causing a leak.). I have tried every throttle position, spraying fuel past the reeds,spraying fuel into cylinder and reinstalling spark plug. My points gap is a .20 and the key is not sheared. My compression is 92. I'm just baffled to what could be going on.

John C
Posts: 303
Joined: Thu Sep 03, 2015 1:32 am

Re: Mcculloch 4hp no start

Postby John C » Sat Apr 14, 2018 10:20 pm

Does the magneto have a cam to operate the points? It could have been installed upside down.

david bartlett
Posts: 1126
Joined: Tue Mar 10, 2015 10:15 pm
Location: Western Maine

Re: Mcculloch 4hp no start

Postby david bartlett » Sat Apr 14, 2018 10:31 pm

Is the exhaust clear? I had a two-cycle pump that would not fire one time. Wasps had plugged the exhaust with mud.
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