Merc 225 poor running

[jsr21]

Hi..I have a 94 merc 225. It has started running poorly over the last couple of days. Poor idle,sputters and sometimes dies when trying to come out of the hole, and surges when running down the lake. Seems to have lost some top end as well. I had the fuel pump rebuilt this spring, and have also tried running sea foam thru it. It has gotten worse with each day I have used it(and I have burned lots of fuel thru it so I don't think it's poor gas).Two weeks ago it ran like a champ. The only thing that has changed is I put Quicksilver synthetic in the tank...Any ideas what I could try myself before taking it into the shop? Thx John

 

[jsr21]

Re: Merc 225 poor running

did compression test last night..all ok..also getting strong spark on all six...any ideas?

 

[jsr21]

Re: Merc 225 poor running

I had it running on my driveway with the muffs on it this aft. When cold, it seems to run fine, then as it warms up it starts spitting and popping out of the top left(if looking at engine from the rear) carb barrel. I held my hand near it and it really pops out a discharge of air, about every 5 seconds or so. Is this a reed problem?

 

[jsr21]

Re: Merc 225 poor running

bump