94 Yamaha L225 V76 internal leak

[frankjohnson]

I have been having irratic rpm at all throttle positionsencluding iidle. Have cleaned carbs twice, compressions 115 on all cylinders. All electrical checks out good. Im thinking I may have sesls bad in engine causing one or more cylinders to rob fuel f
om others. On the sided of both intake manifolds just below the reed valve housing therr is a screw that removed when running you get a pulse of compression. If I were to put a small amount of pressure in one of those holes and check for pressure comming out of one or more of the other holes would that tell me if I have seals leaking by. My manual doesn't tell me what those screws are for nor does it tell me how to check if seals are leaking. Also my enrichment system is sealed and not leaking into carbs.

 

[Jpet0376]

Did you check the condition of the fuel lines? Cracked or delaminated fuel lines can cause similar issues.

 

[frankjohnson]

Yes sir. Replaced all fuel lines from tank to engine and all lines on engine, replaced remote fuel filter and housing, cleaned and flushed filter on engine. The only original lines left are the fuel enrichment lines that I cleaned with pipe cleaners. Also new primer ball. This thing really has me stumped.