4 stroke motors?

[KevinKrey]

I was wondering if anybody on here has any knowledge with 4 stroke motors. I recently bought a honda three wheeler and cant get it to start. I pulled the motor and replaced a lift rod (i think thats what it was) that was broken, and just am having no luck, I know pretty much nothing about these, but I know there are folks on this forum with knowledge on pretty much everything. Just wondering if anybody can offer some assistance.

[Puddlejumper]

Just remember there are three things you need to get an engine to run: fuel, air, spark. If any one of those is not present then it won't run. Does it have fresh fuel? Does the carb deliver fuel to the combustion chamber? Is the float in the carb stuck? Is the air filter clean? are there any air leaks around the carb or combustion chamber? Are your spark plugs good? Are they properly gapped? Are the plug wires cracked or otherwise deteriorated? How is your cylinder compression?

If you replaced a lifter, how is you timing? If your valves are opening at the wrong time then there will be no compression, and therefore no combustion.

[KevinKrey]

The airintake line from the intake box to the carb is not fitting properly and is more or less sitting on the carb. I was assuming this was good enough to get it to start, but by no means is it an air tight seal. Could this be an issue? I know the carb is gettin fuel, but I am not sure how to check if its got it beyond the carb itself.

[viperman]

Kevin, pull a spark plug and just sniff it, this will tell you if you are getting fuel to the cylinders. The air hose running from the box/filter to the carb doesn't really even need to be there, so with it being loose won't be causing the problem. I'm guessing it has a magneto/pull cord start. I'd see if you can replace that (if you are indeed getting fuel to the cylinders). How old are the spark plugs? Are they fresh clean ones, or are they old and grimy? IF they are old and fouled up, there will not be enough of a spark for ignition. If this is the case, definitely replace the plugs, and make sure they are gapped properly. Too big of a gap and the spark won't be able to fire, too little gap and the fuel won't ignite.

[KevinKrey]

The plug is brand new, but it doesnt have a pull start. Its only got a kick start. Fun stuff. I have a new stater to solder on, which I got after being told at a shop that I have "poor spark" so Ill put that on and see if it helps.

[yellowlynn]

One thing I do, depending, is remove the sparkplug and put a few drops of gas in the cylinder. Then if I don't get a pop or two, I can eliminate feed.

Lynn

[Russ Bellinis]

My first question is "What broke the push rod?" I'm presuming that is what you meant by "lift rod?" Usually the only thing that will bend or break a push rod is if the valves get out of time or the valves float from over revving and the valves hit the piston. You may have a broken piston, bent connecting rod, or broken valve inside the engine.

[KevinKrey]

My first question is "What broke the push rod?" I'm presuming that is what you meant by "lift rod?" Usually the only thing that will bend or break a push rod is if the valves get out of time or the valves float from over revving and the valves hit the piston. You may have a broken piston, bent connecting rod, or broken valve inside the engine.

Im not sure, the piston was replaced right before I got it, mayby that says something?... I dont know if the part is a push rod or what, but they are in a chamber right next to the chamber the piston is in, and threre are two of em, one was mangled and bent to heck. Timing might be a part, as the kickstart seems to pop back more than it should when I try kicking it, and I was told this is most likely due to timing.

[Russ Bellinis]

You probably have a push rod type overhead valve engine. The cam shaft that operates the valves is located low down near the crank shaft and operates the valves by pushing up on the push rods. The push rod pushes against a rocker arm which works like a child's teeter totter to push the valves open. Only two things will mangle a push rod. Either the cam is out of time so that the valve is opened when the piston is at the top of it's stroke causing the valve to hit the piston, or the engine gets full of liquid. Liquid won't compress so either the valve bends, the push rod bends or the piston or connecting rod breaks or bends. Most likely the cam shaft is out of time. The engine needs to be torn down to where the timing marks on the cam & crankshaft sprockets or gears as the case may be are lined up correctly. If you install a new push rod without getting the timing correct between the cam and crank, you will just bend the new one. You have two timing specs onyour engine. One is the timing of the Crankshaft to camshaft and the other is the timing for the ignition.