Compression on A Generac 196cc engine

S

SHOESNSOCKS

Member
I was working on a genereac power washer that belongs to my boss. He said it sat for at least a year (maybe more). The fuel tank was empty and the oil was way overfull and smelled like old fuel. I checked the compression and got less than 60psi. Could fuel that leaked down through the engine possibly have caused some damage? Sorry I do not have a engine model number but it I can try to get it later today. The model number on the washer was G0069220.
 
Compression readings on small engines are not of much use on most small engines, as they usually have a compression release of some kind.

Drain it out thoroughly, and fill with fresh oil. Also, put an inline fuel shut offon it,
and shut it off when not in use.
 
If it floods badly when fresh gas is put in, go through the carb and replace parts as needed.

Like a bad float, or leaky needle.
 
You can try to put oil in cylinder and have compression test again. If any change, ring/cylinder can be worn.
If no it can be as said before, compression release - but we need to know engine model to know that. Be sure that chock is not closed and WOT position (but this should not change the world on a small engine...)

Fish explained you all, for sure gas in fuel will do accelerated war / damage in the engine. You should change oil asap and fix the fuel leak ;)
 
If it hasn't been run with the high gas contaminated oil, I would say the cylinder walls and rings are fine. Cannot go by compression readings on a compression release engine. I did a test on a customers generator that wouldn't start last fall and the leakdown test showed less than 10% leakage, but the compression only showed 5 psi. Engine had a clogged muffler issue is the reason it wouldn't run.
 
Thank you everyone for your help. I have already emptied out the oil and put fresh oil in it. There was also already an inline on/off valve for the fuel, and it had been left open.
The engine model number is ST168F-2-A7.
I'm thinking the next step now is to just open the carb and repair or replace. I removed the little plug at the bottom of the bowl to drain any leftover gas and there was definitely some stuff caked up on the end of it.
 
On Generac the engine parts diagram is normally part of the diagram for the equipment parts diagram, So you may need to get the numbers off of the equipment model tag which is a lot of cases is on the lower part of the blower housing on the engine. Will normally start with 00 but some of the newer models can also start with a G with a bunch of numbers behind it.
 
Generac list 60 psi as the minimum compression using a screw in automotive compression gauge per the service manual.

I believe the single cylinder engines used on Generac equipment are made my Loncin, but they are branded as Generac engines, and all parts and other information is from Generac. Generac manufacturers the twin cylinder engines on the over 10K portable generators
 
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