Dead Parsuns F5BM

Hello, I have a cheap Chinese Pasun's F5BM 5hp motor (4 stroke) that has just quit. it is getting gas all the way to the carb, I have replaced and regapped the sparkplug, it does turn, has compression, the lanyard is attached, but the engine simply will not fire. Almost like the lanyard was not attached.

I tried disconnecting the wire from the kill switch, no help.

Any suggestions?

TIA,
Saltbreez

 

How much compression does it have? Is it a two or four stroke? Is there spark at the end of the plug wire, not the spark plug?

 

The compression is unchanged as estimated by my hand pull. This is a four stroke engine.

I do not know if "there spark at the end of the plug wire, not the spark plug".

 

There's only two reasons an engine will not burp - no fuel or no spark. Basic diagnostic procedures suggest you verify that you have both.

Pull the plug, ground it to the powerhead and check for spark at the electrode. If you have a strong spark, you have a fuel delivery issue. If you have a weak or no spark situation, well you know which system to look at.

Guessing will just cause you to replace part after part, so run some basic diagnostic checks. Usually, when they just stop like this, it's something quite simple, like a plugged fuel passage, stuck float, fouled plug, etc.

I don't know much about this specific engine, but have heard complaints about corrosion issues as well as crankcase oil flowing back up the cylinder and locking up the engine if left tilted up and not permitted to drain well, before start up. My impression is these are really quite poorly built machines, designed by inexperienced marine engineers, with inferior materials.

 

The sparkplug sparks when pulled from the engine and grounded on the engine, which would seem to point to the fuel system. Problem is I can confirm fuel up to the carburetor. Perhaps a fouled carb?

 

Typically, the carb gets plugged with varnish and debris, with time and lack of maintenance. A quick carb rebuild, will usually do the trick after a complete cleaning. It could be as simple as a stuck float needle, but usually it's a combination of things, which a cleaning and rebuild will cure.