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Greg 17.5 hp model 31c707 3346 G6 valve problems

#1

G

greggo

I adjusted my valves intake 0.003 - 0.005 I set intake to 0.005 Exhaust 0.005 - 0.007 I set exhaust to 0.007. My engine still drags when trying to start when I do get it started it runs at a very high rpm any suggestions


#2

B

bertsmobile1

When you were setting the valve lash did you check for the ACR bump on the inlet cam ?
If not then the cam shaft is toast
The fact that it is running too fast sort of confirms this as the broke bits of the ACR on the cam can get wedged into the governor or even break it.
The 31 series seem to have more of these failure than other models.


#3

StarTech

StarTech

I think is mainly appears this way because there are so many of the 31 series out there as the 21, 28, and 33 all also use the same camshaft design. As failures yes this camshaft is prone to ACR failure quite regularly and they do take out the oil slinger/governor sometimes. This is why I keep at least one 793880 in stock at all times. Briggs recently superseded the 793880 to 84005207 which is to be noted that Briggs is no longer including lifters (tappets) with the camshaft and must ordered separately. Just a sneaky way of increasing the camshaft kit price without the shop being aware of it. I wouldn't be surprised they start leaving out the oil pump drive shaft too.

I haven't personally ordered the new number yet as my last order was fill with the 793880 camshaft kits.


#4

Fish

Fish

Set the valves at .003 and .005 and see what happens.

Turn the engine over by hand then, and watch the action of the rocker arms.


#5

T

Tinkerer200

Yeah, set Intake to min.
Walt Conner


#6

G

greggo

bertsmobile1 said:
When you were setting the valve lash did you check for the ACR bump on the inlet cam ?
If not then the cam shaft is toast
The fact that it is running too fast sort of confirms this as the broke bits of the ACR on the cam can get wedged into the governor or even break it.
The 31 series seem to have more of these failure than other models.
Click to expand...
No I sure didn't but I will definitely check thanks


#7

G

greggo

StarTech said:
I think is mainly appears this way because there are so many of the 31 series out there as the 21, 28, and 33 all also use the same camshaft design. As failures yes this camshaft is prone to ACR failure quite regularly and they do take out the oil slinger/governor sometimes. This is why I keep at least one 793880 in stock at all times. Briggs recently superseded the 793880 to 84005207 which is to be noted that Briggs is no longer including lifters (tappets) with the camshaft and must ordered separately. Just a sneaky way of increasing the camshaft kit price without the shop being aware of it. I wouldn't be surprised they start leaving out the oil pump drive shaft too.

I haven't personally ordered the new number yet as my last order was fill with the 793880 camshaft kits.
Click to expand...
Thanks for the information I will hang on to these part numbers


#8

G

greggo

Fish said:
Set the valves at .003 and .005 and see what happens.

Turn the engine over by hand then, and watch the action of the rocker arms.
Click to expand...
Ok thanks


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