blackchevy3de
Active Member
- Joined
- Oct 24, 2013
- Threads
- 34
- Messages
- 66
I checked the compression and only has 50 psi, removed muffler no scratches, no leaking seals im thinking rings
bt 130 back pack blower
- Thread starter blackchevy3de
- Start date
d_sharier
Well-Known Member
- Joined
- Oct 20, 2014
- Threads
- 11
- Messages
- 146
Ok, so 50 psi is no good. New we like to see around 150 psi. When we see numbers nearing 100 psi on this type of equipment, rebuild starts coming into the conversation.
A few more questions and please don't be offended if they seem over simplified.
1. What style of tester are you using? Type that threads into the cylinder, or older style with rubber tip that must be held in place against the cylinder.
2. Is the seal between the tester and cylinder good? soapy water around the hole with the line threaded into it. Pull the engine over to check compression, any bubbles?
3. When you are checking the compression are you pulling the engine over several times until the number stops rising? or just pulling over 1 time?
If all of these are ok and you don't see any scoring on the piston from the exhaust side,next I would check the rings. In through the exhaust port you should be able to visualize both rings. Are they both present? I use a small wooden dowel (like a tooth pick) to depress each ring. This checks for good tension and to see if the rings are free floating. You should be able to feel a little "bounce" when depressing each.
If that check is ok, next I would remove the intake side parts. Air box and carburetor. You should be able to visualize the piston the same way through this port. You will only be able to see the bottom half though. Check for scoring here too. If scoring is present on the intake side it is usually a result of ingestion of foreign material. I.E. dirt.
If you don't find any scoring on either side of the piston and the top half of the cylinder is free from leaks, then the next step is to pull the engine and remove the cylinder to inspect.
Let me know what you come up with
A few more questions and please don't be offended if they seem over simplified.
1. What style of tester are you using? Type that threads into the cylinder, or older style with rubber tip that must be held in place against the cylinder.
2. Is the seal between the tester and cylinder good? soapy water around the hole with the line threaded into it. Pull the engine over to check compression, any bubbles?
3. When you are checking the compression are you pulling the engine over several times until the number stops rising? or just pulling over 1 time?
If all of these are ok and you don't see any scoring on the piston from the exhaust side,next I would check the rings. In through the exhaust port you should be able to visualize both rings. Are they both present? I use a small wooden dowel (like a tooth pick) to depress each ring. This checks for good tension and to see if the rings are free floating. You should be able to feel a little "bounce" when depressing each.
If that check is ok, next I would remove the intake side parts. Air box and carburetor. You should be able to visualize the piston the same way through this port. You will only be able to see the bottom half though. Check for scoring here too. If scoring is present on the intake side it is usually a result of ingestion of foreign material. I.E. dirt.
If you don't find any scoring on either side of the piston and the top half of the cylinder is free from leaks, then the next step is to pull the engine and remove the cylinder to inspect.
Let me know what you come up with