2hp knock

[mike n]

I’ve had that happen with coils hitting flywheel but this one doesn’t seem to be.i will double check it anyway. I’ve worked a bunch of other motors but this one seems to be the most frustrating. I like that it’s small and lightweight but I definitely like my old 3hp’s better

mn

[mike n]

I’ll double check splines too

mn

[fleetwin]

I hear ya about the price of the new rod bearing…I’ve never seen alot of “wear” on these things, usually get ruined from rust… It is possible that you left out a needle though, that would make it sloppy in this area…It’s not tough to pull off the intake and get in there to push the rod around on the crank in an effort to detect excess slop…
As far as the gearcase…You mention the oil was OK when you changed it, so it is very unlikely that gears are damaged…But, anything is possible….You could try removing the gearcase, then starting the engine up in a bucket of water (to quiet it a bit so you can hear the powerhead)… This might help rule out gearcase/spline issues. Keep in mind, there is no oring on the driveshaft on these engines, so crank splines get destroyed/worn pretty often….
PS: Don’t rule out that recoil too quickly, it is easy enough to run the engine without it to see if the noise goes away….

• This reply was modified 4 years, 7 months ago by fleetwin.

[mike n]

Figured I’d show these pics. I’ll double check that stuff

mn

• This reply was modified 4 years, 7 months ago by Mumbles.

[fleetwin]

OK, yes, that second picture looks troubling….Did it look like this when you first pulled it apart? Don’t be offended, but I’m assuming you have the rod cap oriented properly, there are very small line up tabs that need to match up. Do you have the right number of needles in there? Those little buggers are super easy to lose…I lost one once, it ended up jamming between the piston and intake port…”Found it”….
Do you have those needle liners properly oriented and seated in the rod? If not, the rod may have never been properly secured to the cap, even though the proper torque was used. Unfortunately, I think you better start with a new needle/liner set…Perhaps you can find a reasonably priced on ebay…Or, perhaps from a member…I guess I would line up the rod cap and rod, the perhaps secure the halves off the crank without the liners to see if the rod somehow get distorted from improper installation..Needless to say, it the rod has become distorted, it is not usable…

[mike n]

Not offended at all. That’s why I’m asking guys on this forum. I’m an auto mechanic and I try to be as thorough as possible. When I replaced the piston,the bearing sleeve did look like this.i never removed the sleeves so I know I put the cap back on right because it really only goes one way. Not sure what that bearing is supposed to look like,have nothing to compare to but It does feel a little rough when you run your fingernail across the discolored part

mn

[fleetwin]

OK, so rod cap misalignment seems out of the question…Like you said, you never removed the liner, so it will only fit one way…Nonetheless, that liner looks to have been overheated, so should be replaced…
How about this for a test: Simply reinstall the piston into the cylinder and reinstall the original needles/liner onto the crank, snug up the rod screws…Now, just rock the piston back and forth to check for rod slop on the crank…Again, please make sure you have all the needles, I don’t know how many there are off hand but can look it up if you need me to…Like frank says, use petroleum jelly on the needles to keep them in place during installation…If all seems OK, then I would try to find a new liner/needle set… Don’t forget to torque the rod to spec, which isn’t very much…
Keep in mind that the wrist pin end of that rod had a needle bearing also, perhaps that is worn and is sloppy…Wear is not that likely, unless caused by rust…I’m assuming you had a look at it when you replaced the piston…Any chance some of the needles fell out when you replaced the piston? I’m pretty sure those needles are captured in there and should not have been able to fall out, but anything is possible….

[mike n]

Those needles look to be captured.they look ok along with the wristpin.of course that’s the cheap bearing.ill try rocking the piston as you said but can’t get to it right away. I saw the amount of needles posted somewhere. I’ll find it and double check. Thanks for help. I’ll post when I get back on it

mn

[Mumbles]

The upper liner is definitely showing signs of wear and is more than likely the cause of the knock. The needles should be shiny and not blue or purple colored which shows signs of heat. Vaseline can be used to hold them in place and it washes out as soon as the motor starts. Grease doesn’t. A pair of tweezers helps to get them placed properly to. I think there are thirty needles used in these bearings and each one of them has to be accounted for. Dropping one into the motor and not noticing it is a recipe for disaster.

[mike n]

I think you’re right about having 30 needles. I will check. I will look for a new bearing either way.thanks

mn

[Author]

Posts