Need advice ,opinions on 1872 engine problem

[cvenezia]

I have a nice 1872. It is in great shape but recently it has developed a noise in the right cylinder. It still has compression 95 on left and 105 on right but something does not sound right. have not noticed loss in power. kinda sounds like an extra knock like a diesel but not as regular sometimes there some not. Now I am trying to decide what to do. Should I rebuild, buy a rebuilt or used engine or I have read about the repower motor(briggs) which is supposedly a newer better replacement. Cost is a concern and it is still running for how long I do not know. Any thoughts will be appreciated.

 

[jchamberlin]

Charles, my opinion is free, so take it for what its worth, but I'm curious about what sort of noise you're hearing, and why you feel its coming from the right side? If the noise is a bearing --fix it ASAP.

 

[cvenezia]

Jeremiah, I think the noise is on right side because if I pull the right plug wire the noise goes away if I pull the left it does not go away. I will describe the noise the best I can. It is not heard at idle or full throttle. It sounds like a background noise. you have the engine noise then randomly you hear "bang bang-----------bang. If it is a bearing would the noise go away when the plug wire is pulled? Any way to confirm the bearing.
Thanks
charles

 

[jchamberlin]

Charles, I don't like the sound of what you're telling me. I'm no expert, but it seems to me that the two likely places to be making a noise are both bad: either a bearing is getting ready to go, or you're hearing a piston slap. Logically speaking, the sound appears to be related to the combustion stroke.

I can only share my limited experience with diagnosing engine sounds. My 16 HP Briggs & Stratton made a knocking sound that even the loud exhaust could not hide. It was most obvious to me when I left the tractor idling in the back yard while I went to the front yard. The exhaust note dimmed, but the knock penetrated the distance. The rod let go when the oil drained out after the crankcase bolt loosened and fell out. The failure was catastrophic --at least to the rod, and the piston. Since the same bearing surface had already been under cut, and the piston over-bored, there was nothing to be done.

If it were me I think the situation warrants opening it up to see what is the matter. Again, my advice is free, so treat it for what it is worth.

 

[jdiederichs]

Another possibility would be an exhaust valve seat that is now loose. To prevent any further damage I would not run the engine until that cylinder head is removed. Once off you can manually turn over the engine until that valve opens, at which time you can inspect the valve seat. Use a "dental" pick to check if it is loose, as well as visually looking for displaced metal around the seat's location. Next crank the engine with the starter and watch the seat.

 

[cvenezia]

Took tractor to get looked at, Two new plugs,and carburator adjustment later for a total cost of $5 and the engine is running great. Thanks for all the replies. Seems it was running too rich.

 

[jchamberlin]

Charles: Thanks for the update. I guess the spark plug would be combustion related. Glad it wasn't mechanical.

 

[ameek]

so like he had some spark knock. Also to maybe prevent it from doing it again in the future maybe try and pull the head off and clean it. It should be cleaned ever 250-500 hrs to remove carbon deposits that cause spark knock.