Very Loud Popping Sound, Loss of Power and Speed on B & S Engine

i have a troy bilt pedal drive lawn tractor (model LTX-1842) with a briggs and stratton 18 hp I/C OHV engine (model 31D777, type 0233E1)...

the engine has a very loud popping sound...the lawn mower doesn't move as fast as it once did, and when the blades are engaged, loss of power...

the mower is extremely loud...i have changed the spark plug, oil, and air filter...

the popping sound is troubling and i can't figure out what it could be...

thanks...

 

The problem is with the valvetrain. Pull the valve cover off and look at the rocker arms and push rods. I'm guessing either a rocker arm is off or very loose, or the camshaft has worn a lobe off. Both are common problems.

 

so, would that be any easy fix or an inexpensive fix??? or is it a problem where i just need to replace the engine???

 

Adjusting the valves is pretty easy and just takes a few minutes but replacing a camshaft is more advanced and time consuming since you have to open the case of the engine, but it's still not a bad job.

 

thanks...so, just curious about what actually makes that sound??? what is going on internally to make the engine produce such a loud noise...

does anyone know any online resources i could use to help me tackle this job over a weekend or something???

 

You can do a search online for "adjusting briggs and stratton ohv" and several videos that might be easier to follow than a word description.

 

ok guys...got the estimate from a local small engine shop who does the warranty work for troy bilt lawnt tractors...

when he took the air filter off, he first noticed a lot of black dirt in the hole that goes down to the carb...he put his finger in it and wiped out a lot of black gunk...he said that is dirt from a dirty air filter...he then said when he sees this, they go ahead and estimate the job including a cam shaft...he also showed me air coming out of the carb when running...he put a piece of paper over the hole going down to the carb and cranked it...he said that should be sucking air in...instead, it was blowing back out through the carb and blowing the paper around...he said they checked the compression and it has lost compression...

so, he said they would take the head off, replace the head gasket, replace the cam shaft (due to a probable lobe being worn down), do something to the valves, adjust the valves, oil change and filter for right at 311 bucks...

my question is whether or not a fix like this would make the mower last a couple or more years...i would hate to sink that money into and it only last one season...after a job like this, will it have a good chance to last me a lot longer??? i am just no familiar enough with small engine repairs to know if this is a simple and easy fix and will make the engine last longer...

any opinions would be appreciated...the repair shop did want to me know i had time to make a decision, he didn't want to pressure me to fixing it or not fixing it...he told me whatever he does to, he will show me all the parts he took off and not charge me for what it doesn't need...he told he doesn't like people to to do that to him...he brought me back through the shop and explained in detail about the engine and the problem...he even took the time to take one of his repairs guys off a job to find a cam shaft that was taken off last week to show my a worn lobe...

thanks...

 

Since the engine is basically dead now, fixing it should buy you at least several years. There may be other, non-related things that go wrong but that's to be expected with any engine with some age.

Another thing to consider is taking the engine to a local high school that has a small engine or mechanic's course and let them repair it as a project.

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20++ years ago my father gave me his father's rototiller. After 40 years it was in need of an overhaul. I checked around and did not have the money to pay a shop to overhaul it for me so I signed up for night classes in small engine repair at the local high school. The cost of the class and parts for my engine was about half the cost of hiring the repair and the class was a lot of fun, I learned a lot and I came home with a engine I rebuilt myself.

 

I've done a few of these with bad camshafts. There is no reason it shouldn't run for several more years unless there are other wear issues with the engine too. It sounds like a cam problem, but if it happened suddenly and not progressively, I would be looking at the valves first. The cam wears down over time.

 

the engine is a 2003 engine...never had a cam shaft replaced...it has over 300 hours...it mowed a 2-3 acre yard (very dry yard) from 2003 - 2010...starting last summer and just the month of may this year, it mowed a 1/3 acre yard...

the mechanic did say the area going into the carb had a lot of dirt deposit on the side...he stuck his finger in it and wiped out a lot of black stuff of the sides...