engine quitting
 

hi! i have a 25cc homelite, all stock.i put it in an airboat. i have test fired it and noticed that everytime i pass the half throttle mark, the engine kind of bogged down or losing power and eventually died. at half throttle it was doing ok, lots of power. what causes this problem? i have taken this from a blower, and i have already noticed this when it was still in the blower although it doesnt really quit then, just lost power and rpm.
i am using an apc 15x13 prop on this.
thanks a lot

RE: engine quitting
 

Sounds like the high speed needle valve is too lean. I'm not familiar with this exact engine, but generally on gas engines the carburetors have two needle valves. One is used to adjust it at idle and the other for full throttle. Look at the carb to see if it has two adjustment screws. On my gas engine they are clearly marked "H" and "L".

RE: engine quitting
 

yes there's two needle in there marked H & L. i have thinkered with the L speed and did found difference. but i cant turn the H. which direction should i turn it? CW or CCW?

RE: engine quitting
 

ccw rich, cw lean

RE: engine quitting
 

ok thanks! i'll try that. one more thing, how do you enlarge the hole for the prop shaft without using a prop reamer or having a drill press. i only got a drill and dremel. i do have a dremel router table.
thanks!

RE: engine quitting
 

You need a reemer to get the blades tracking directly behind each other. Drill press or reemer only option. Home depot sells reemers or any aircraft hobby shop.

RE: engine quitting
 

this engines come out of the factory with an exhaust and carb calculated to don´t go over the 7000 rpm. so if open the H needle dont result try a bigger carb

RE: engine quitting
 

Just for what it's worth - Homelite blower engines come with a carb that does not have a throttle stop. Is it possible that you are going past full throttle and heading back to idle?........( had to ask)

RE: engine quitting
 

well i guess it ok if it will turn that prop in the 7k range.but why is it like bogging down when going past half throttle?
i have tried it yesterday though and it seems ok, i was able to go full throttle and sounds ok, seems to go along ok without bogging down. i havent change any H needle settings yet. it was in the evening so i guess it has to do with the needle set too lean.

bob i guess thats wats my problem, when going past half throttle the engines slows down and then dies.

if i am to buy a bigger carb, is it available for commercial use? i mean, are there bigger carbs out there that are direct replacement for blowers or trimmers or chainsaws that you can readily buy at the engine shop or at engine parts dealer? because hobbywise, i will never be able to buy it.

RE: engine quitting
 

i have checked my engine last nyt and it seems that the high speed needle cant be adjusted. the picture below shows the carb. red arrow is the low speed and blue is the high speed. anything i can do to make it adjustable?

RE: engine quitting
 

I see that you are using the stock muffler that came with the engine.Check to make sure that the spark arrester screens are not plugged up with carbon as this will lead to excessive back pressure in the muffler and symptoms similiar to what you are describing.I discovered this problem myself a while back when trying to tune up a weed wacker that just wouldn't run right no matter which way you turned the needle valves.After thoroughly inspecting the engine a bit further,I noticed the spark arrester screen was practically closed over with carbon.I removed the screen and fired up the engine again.The engine would now go to full power when throttled up and just plain had better performance all around.What a difference:).Some park arrester screens are mounted with a screw on the outside of the muffler but some such as yours are manufactured with the screen actually inside the muffler and can't be easily removed.If you soak the muffler in a container of lacquer thinner for a few days,it will help to break down the crap that clogs the arrester screen and the engine will be able to breath much easier due to the lack of back pressure.Old tooth brushes come in handy for doing this kind of cleaning work.Gutting the muffler all together and installing larger exhaust stacks will improve your performance factor qiute a bit also.If it's not a carb related problem that you are having,take a gander at your muffler and see if you don't have the same problem that i've just described above.Good luck!;)

RE: engine quitting
 

The H needle is not adjustable, it comes from factory in a fixed position, you need a bigger carburetos with L & H needles

RE: engine quitting
 

turbo, i have already taken the spark resistor. i guess it has more to do with the H needle setting which unfortunately is not adjustable. i guess i just have to find a carburator.
platero, are all carburators interchangable? i mean if i buy a carburator for a 50cc chain saw, will it fit this 25cc homie? cause i assume its a bigger carb than mine.
thanks foir all your help.

RE: engine quitting
 

50cc carburetor dont fit in 25 Homelite, the 35cc Homelite carb is the choice

RE: engine quitting
 

still you can remove much aluminum from that motor see my photos at
http://www.hpignitions.com.ar/reform...lite_25_cc.htm

RE: engine quitting
 

will carb from other manufacturer fit homies? like kawasaki or stihl? or robin?

RE: engine quitting
 

Yes,as they all will either use a Walbro,Zama or Tillotson brand carburetor.They are all interchangeable providing you keep the venturi size comparable to one another.There might be problems related to position of throttle and choke levers and such as there are many different ways of actuating these devices and you might have to get a little creative to get them to work with your original set up your using.The largest venturi size you will want to use on that engine is around 11.1 mm.Any larger than that and your engine will start to experience transitioning problems.There is such a thing as "over sizing" the carb TOO much;):).If you do a search for 11.1 mm carbs in this forum,you will come up with a wealth of information on the subject.

RE: engine quitting
 

Should be able to pick one up at a local chainsaw, mower repair shop. Most are pretty helpfull. Should be a model number stamped in the side, such as WA or WT as a place to start.

RE: engine quitting
 

hi! does anyone know if a certain carburator on a stihl engine be usable in the homie? and if it does, can you give me stihl part no? i'd like to call a stihl distributor here and would like to know first what part am i looking for. they dont know homelites here. :D
thanks a lot

RE: engine quitting
 

Ernest2,the question you want to be asking first is what brand of carb is commonly used on Stihl engines?The engine shop should be able to tell you that as they are the ones selling them.Once you have narrowed down what brand of carbs they are able to order,then you can narrow down the search for a 11.1mm size venturi carb.I am sure though that there is someone here in this forum that knows the answer to that question already regarding Stihl products and the carb brands that they use.Any Zama or Walbro brand carb with a venturi size of 11.1mm should suffice.Be aware that a brand new carburetor from your local small engine shop can get to be quite pricey.Look to see if any any used carbs are available first and you might be able to save a few bucks.

RE: engine quitting
 

Ernest:
Carb from a Stihl model 015 should work. It's a Walbro HDC with adjustable high and low speed jets. Don't know the throat size but it's a 32 cc engine so it should be close.

RE: engine quitting
 

thanks!! well i will be calling the dealer as its hard to find engine shops here (for small engine).
one thing though, what equipment is a stihl model 015? is it a chain saw or a cutter>?
thanks again,
ernest

RE: engine quitting
 

Cutter, Trimmer

RE: engine quitting
 

i have tried another prop today and the engine loses power much earlier than the other prop. will too big of a prop or too much pithc causes an engine to lose power and quit?

RE: engine quitting
 

I liked the 16-10 best on my Homelight 25. A friend always used a 18-8.

Enjoy,

Jim