Engine doesn't run

kart_goes_brrr

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So, Ive done a **** load of mods on my 196cc (stock metal cam, billet rod, flat top piston, 22lbs springs, mikuni vm22, aluminum flywheel) but it doesn't run. I don't know what to do, should I try starter fluid or should I search for the problem first? Please help, I spent over 6 months working on this engine, I don't want it to fail😭🙏 (no photos for the moment, I can't go outside because its a literal oven (43°C))
 

Hellion

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Oh sh*t!

Be funny if it was, you know, out of phase and the valves were opening when they should be closing. No telling what you did wrong but it’s not rocket science.

Sure, try starting fluid, or raw fuel dribbled in through the carburetor and see if it puffs and combusts
 

kart_goes_brrr

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Oh sh*t!

Be funny if it was, you know, out of phase and the valves were opening when they should be closing. No telling what you did wrong but it’s not rocket science.
I mean I aligned the cam with the crank with the dots, I feel like the cam is scratching the block because whenever I pull, I hear some light scratching. I checked however but it's fine, it was just a bit out of place, I put it back correctly this time, pulled over 10 times, nothing.
 

Hellion

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You know the drill. Three things required (maybe more, I’m not sure, I’m still drinking coffee!):

Fuel
Spark
Compression
 

kart_goes_brrr

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Compression, check
Spark, how do I check it? The kit is brand new so It probably works
Fuel, check, the fuel is kinda old I might change it, it's still flammable tho
 

Hellion

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Does the engine have a kill switch installed, or have its stock on/off switch? It could be off, literally set to OFF thereby killing the spark. Or the switch could be faulty meaning you cannot turn it on (always off). You can check the spark by…


Spark plug may be faulty (rare but it happens). Try a new plug
Could be a bad ignition coil

May not have enough fuel to start/run — verify and adjust carburetor as needed
May not have enough compression to start/run — verify with a compression gauge

Are you using the choke? Most of the engines I have require choke all the time (hot or cold engine) to get it started.
 

kart_goes_brrr

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Does the engine have a kill switch installed, or have its stock on/off switch? It could be off, literally set to OFF thereby killing the spark. Or the switch could be faulty meaning you cannot turn it on (always off). You can check the spark by…


Spark plug may be faulty (rare but it happens). Try a new plug
Could be a bad ignition coil

May not have enough fuel to start/run — verify and adjust carburetor as needed
May not have enough compression to start/run — verify with a compression gauge

Are you using the choke? Most of the engines I have require choke all the time (hot or cold engine) to get it started.
I'll try that method to test for spark, also the on off switch is new too so it should work, and yes I use the choke whenever I start the engine (vm22 mikuni carb), the gas tank is full to the brim, and the fuel is flowing too. I can feel the compression, it's really strong. So I'll just check for spark, if there is and the engine still doesn't run, I'll just take it to the mechanic.
 

Hellion

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Starting fluid is of course a good useful thing to have. Most gearheads warn against using it all the time because there are people out there that absolutely RELY on that stuff to start their engine. They're pre-charging the engine cylinders and cheating their way past the problem(s) with their engine.

I think the biggest issue with starting fluid is you're washing the cylinder and piston with a very light and volatile SOLVENT; you are washing away the engine oil on the bore and the piston rings -- so after "hosing down" the cylinder with starting fluid, you're basically starting the engine dry. There's people who use a lot of it too --- a long 5 second spray of starting fluid into the intake. Ouch!
 

bob58o

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I'll just take it to the mechanic.
don’t do that. We’ll get it running for you. If there is spark, that’s good. Well check timing next. Did your camshaft / crankshaft timing dots align when you put the camshaft back in? Did you install a flywheel key on the crankshaft when installing the flywheel? Did you set valve lash when the valve springs were relaxed???
These are the things you need to learn that you won’t by letting a mechanic fix it.
 

Hellion

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Fuel, Spark, compression, and timing
Thanks. Compression, Fuel, Spark all at the proper Time.

I place my $ on this bet please.
Kill switch wiring
Uh oh. It's usually something simple and dumb.

don’t do that. We’ll get it running for you
Agreed. We've got to be our own mechanics before (mods) and after (mods).

What's the status, kart_goes_brrr? There's no shame in admitting a mistake here. We've all "been there and done that" and still do make mistakes, most of them stupid mistakes.

:sifone::cheers2:
 

kart_goes_brrr

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Thanks. Compression, Fuel, Spark all at the proper Time.


Uh oh. It's usually something simple and dumb.


Agreed. We've got to be our own mechanics before (mods) and after (mods).

What's the status, kart_goes_brrr? There's no shame in admitting a mistake here. We've all "been there and done that" and still do make mistakes, most of them stupid mistakes.

:sifone::cheers2:
Alright so I couldn't check many of the things since I'm spending some time with family, but I checked for compression and it's good, I'll get some new fuel on the way home, haven't checked spark yet, and yes, the dots on the crank and cam are aligned correctly.
I place my $ on this bet please.
Kill switch wiring
Here's the wiring, you might be right 😭61NmRXBm4kL._UF1000,1000_QL80__edit_723905864195673.jpg
Also in the small text, it's "in" not "is".
Will you win the bet bob58o?
 
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