[BRENT in 10-uh-C]

Generally the reasons are these in no particular order:

Retarded Ignition Timing.

Too lean of carburetor fuel mixture.

Radiator tubes clogged.

Radiator fins fractured from tubes and cannot dissipate heat properly.


Your system is not under pressure so a loose Motometer is an unlikely cause. Also, too full of a radiator tank can allow water to overflow giving the appearance of overheating out the overflow. Make sure your water level is about an inch above the core or baffles and try again. If it is indeed pushing water out the overflow, then start by checking the ignition timing and fuel mixture. If the problem persists, use an infrared temperature gun to determine if there are cool spots in areas of the radiator core which would indicate heat from the water is not being dissipated correctly.

There are other less-common things that could cause overheating but for now as not to confuse you as a "newbie", lets get the basics covered first if you like and we'll explore other areas if this doesn't produce results.

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