2 or 4 stroke

[modelengineer]

It's true for high performance 2-strokes, but most industrial ones last a LONG time.

 

[Kaptain Krunch]

i read somewhere that 2 stroke engines don't last as long as 4 stroke due to lubrication and you need to strip & rebuild often, anyone had any probs with there's?
ps. bought a 2 stroke engine today & gonna strip it tomorrow give it a polish etc. not sure what hp it is tho

Give it a polish? that wont do ****. if your stripping it down, Hone the cylinder, replace rings, get rid of carbon build up on piston and exhaust port, replace crank bearings and all seals, clean the carb and give it a rebuild kit.

 

[stephenm2682]

i meant cleaning the engine, just referred to it as polish. i will see if i can find a rebuild kit.

 

[stephenm2682]

how do i tell if my lawnmower engine is 2 or 4 stroke? tried the mower it today ran okay, noisey but wouldn't turn off only when i turned petrol tap off? help

 

[briggsman]

I guess the easiest way would to be to look and see if it has regular valves like the Honda clone or the briggs flathead, another way is that there will be a cylinder head that can be removed on top of a 2stroke usually held on with 4nuts and also the cylinder assy can also be removed(called the jug) directly underneith the cylinder head.
hope this helps

 

[stephenm2682]

doesn't 2 stroke petrol need a mix with oil? mine as a dipstick & oil filler cap screw? any ideas on why it won't turn off? i think it's the throttle cable sticking.

 

[briggsman]

If it has a oil dip stick it is a 4 stroke

 

[stephenm2682]

don't think i'll be using it as it only as 75cc (1.5hp?) 4 stroke engine, probably only do 5mph lol.

 

[Kaptain Krunch]

75cc is probably more than 1.5hp, since its industrial i'd expect arpund 3 hp maybe a lil more, so you could make an on road kiddie kart with it but it wont be very powerful.

 

[stephenm2682]

any way of boosting it or is it cheaper looking for something bigger?

 

[Kaptain Krunch]

Your best off trying to find an old snowblower, generator, or water pump that runs, but has some problem, and salvaging the engine.

 

[stephenm2682]

yeah thanks again for your help kaptain.

 

[stephenm2682]

just curious but what gear ratio would i need for that engine?

 

[stephenm2682]

anyone?
and how accurate is the speed calculator as it say'sabout 50mph for my engine? doesn't seem possible

 

[modelengineer]

It doesn't take into account the power of your engine. If you geared it to do 50mph at 5,000? rpm, then you just won't be able to get it to 5,000 rpm. The calculator only works if the engine has enough power to pull that RPM at that gearing.

 

[stephenm2682]

well the engine runs at 3000rpm and i inputted that in the calculator?

 

[stephenm2682]

would that speed be incorrect for a 75cc engine? what gear ratio would suit it? thank you

 

[ed1380]

im guessing 2 stroke so 8-10krpm. at least a 10:a ratio.
does it have a tranny or crank output

 

[stephenm2682]

it's a 4 stroke. and its crank output.

 

[Kaptain Krunch]

For that engine you should aim for a 7:1 ratio, you say it runs 3k rpm, what did the engine come off, most industrial engines run around 3600 rpms. But either way with that engine i'd go around 7:1 if your using standart 12 or 14 inch tires, if they are some other size use the speed calculator to find a ratio that will give you a top speed of about 20mph.