Briggs 15.5 Powercare Knocking - low speed

[stim141]

Had to replace the compression release. Was running - I thought fine the entire summer. Don't remember if there was a knock. Reassembled, started up perfectly but it has a knocking sound at low RPMS - think its still there at higher rpms. Checked valve clearance and reset - same results. No bent rods - intake or exhaust. Drained oil - amber going in - grey/black going out after only a few minutes of run time which isn't normal. Cylinder seems ok and compression is fine. Pulled it and opened up again. I don't see anything abnormal. When I pull down and up with the engine facing bottom up there is play at the counterweight with the counterweight 44links. Any suggestions on where to start?

 

[Craftsman Garage]

Grab the con rod and if there is any movement, that's your knock. Just replace the con rod.

 

[stim141]

Thanks for the quick response. Possibly. The amount of aluminum in the oil seems like something is disintegrating badly esp only running it for a few minutes. To waste more on parts and the time to pull it, put it back together I think it isn't worth it. I need to cut and mulch leaves this week. Con rod + two counterweight arms is about 150 shipped. My time and if it doesn't work ! Bought the Pony for 325 in March - cut the entire season. Used to use a service which charged around 1850 so it paid for itself already. Found a replacement which should be 31R907-0001-G1 for around 630 new in the box shipped free. Know its a waste of money going this way but if I get a season or two it will pay for itself several times over.

I have to figure out the wiring on the new engine - old harness doesn't seem to match the new engine. Should be able to work it out.

 

[Craftsman Garage]

Upload a pic of the engine and wiring?

 

[stim141]

The connecting rod has side to side play and it makes a knocking noise when I do that. I assume that isn't normal. The aluminum fine particles are a concern that something else got trashed or it was the rod and counterweight arms self destructing as well.

Upload a pic of the engine and wiring?

 

[stim141]

Upload a pic of the engine and wiring?

On the original engine there is a connector with a black and white which goes to the carb. Then there is a black and red going to the alternator. The connector from the mower has it in the connector as orange and red. The new engine only has a yellow going to a block with a red exiting the block. The black is grounded on the black box on the engine. Easy to splice the black/grey to the connector and the red from the connector to the red on the engine but where do I connect the black wire from the connector to the engine?

 

[ILENGINE]

The black and grey wires from the old engine can be connected to the corresponding grey and black in the double connector on the new engine. The grey is battery power to the fuel solenoid on the carb and will be powered with the key in the on and start positions. The black is the kill wire for the ignition module. That wire is grounded in the key off and open in the key on. That wire can never see battery voltage unless you want to replace the ignition on the new engine. The red and orance can be spliced together and connected to the single red connector coming from the square box aka voltage regulator. And if the mower doesn't have headlights or you don't care then you just need to connect the red to the single red on the box and ignore the orange.

 

[Tiger Small Engine]

Thanks for the quick response. Possibly. The amount of aluminum in the oil seems like something is disintegrating badly esp only running it for a few minutes. To waste more on parts and the time to pull it, put it back together I think it isn't worth it. I need to cut and mulch leaves this week. Con rod + two counterweight arms is about 150 shipped. My time and if it doesn't work ! Bought the Pony for 325 in March - cut the entire season. Used to use a service which charged around 1850 so it paid for itself already. Found a replacement which should be 31R907-0001-G1 for around 630 new in the box shipped free. Know its a waste of money going this way but if I get a season or two it will pay for itself several times over.

I have to figure out the wiring on the new engine - old harness doesn't seem to match the new engine. Should be able to work it out.

For around $1000 (mower purchase plus new engine) plus your labor, you can buy two good used riding mowers.