I have a 6 yr old scotts lawn tracter with the two cylinder 25hp Intek engine by B&S. It runs good, does not smoke, missfire or stall. It still cuts fine, Been using valvoline sinthetic oil the whole time, But over last few months, There has been a chattering noise when the engine speed is at 3/4 or more. It does not seem to affect performance, just want to know if its a ticking bomb???
25 hp B&S Intek engine, chattering noise
- Thread starter AlanJW
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It might be time to adjust the valves.
BTW, if you let an exhaust valve get too far out of adjustment it will burn the valve.
+1, Check the valve adjustment.
Originally Posted By: JimPghPA
BTW, if you let an exhaust valve get too far out of adjustment it will burn the valve.
A valve will burn only if the valve lash clearance is too tight not allowing the valve to properly seat. Valve chatter is usually the result of valves set too loose. Slightly loose is far better than tight. As the saying goes, "Tappy valves are happy valves."
I'm a bit confused with the chatter only being heard at a certain rev range. I.e. 3/4 throttle. If the problem were valve noise, it should increase as revs build.
I'd say look around for something that might be loose on the engine. Possible a cooling shroud or piece that might be vibrating.
Another diagnostic tip is to take a long screw driver or suitable long metal rod with a handle on the end and put the handle to your ear and the hard end on the engine to use as a rudimentary stethoscope to listen for the source of the noise. Move the tip around the engine to find where the noise is the loudest.
BTW, if you let an exhaust valve get too far out of adjustment it will burn the valve.
A valve will burn only if the valve lash clearance is too tight not allowing the valve to properly seat. Valve chatter is usually the result of valves set too loose. Slightly loose is far better than tight. As the saying goes, "Tappy valves are happy valves."
I'm a bit confused with the chatter only being heard at a certain rev range. I.e. 3/4 throttle. If the problem were valve noise, it should increase as revs build.
I'd say look around for something that might be loose on the engine. Possible a cooling shroud or piece that might be vibrating.
Another diagnostic tip is to take a long screw driver or suitable long metal rod with a handle on the end and put the handle to your ear and the hard end on the engine to use as a rudimentary stethoscope to listen for the source of the noise. Move the tip around the engine to find where the noise is the loudest.
Ya, the noise seems to progress the warmer the engine, and the higher the engine speed, the noise is a harmanic light and annoying chattering sound, I talked to a repair man today, he seems to think it has to do with the ethynol in fuel, but i figured that would pose a performance issue. And when I check the valves, what should I be looking for, Can I adjust these valves, should I? I am a little worried, dont want to loose a good engine do to poor knowledge on my part
JTK
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Originally Posted By: boraticus
...I'd say look around for something that might be loose on the engine. Possible a cooling shroud or piece that might be vibrating.
Exactly. This very well could be something on the chassis. Idlers, pulleys, springs, exhaust system...
Joel
...I'd say look around for something that might be loose on the engine. Possible a cooling shroud or piece that might be vibrating.
Exactly. This very well could be something on the chassis. Idlers, pulleys, springs, exhaust system...
Joel
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If its like the Intek I took apart, the valves are adjustable like older automotive valve trains...you'll need a feeler gauge, proper socket for the nut, and the valve lash specifications...it is fairly easy to do.
ya, I was hoping it was like a vibration, but honestly, everything pretty sound, and tight, I just dumped quite a bit of money into belts, pulleys, bearings, hubs, and a lot of other parts. I mean the tracter is 7 yrs old, so I expect some chassie noise and some engine noise, but this one just kinda popped out of no wear.
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