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Mercruiser 350 running rich weak holeshot

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Hi guys, I have a Mercruiser 350 with a Holley 4160 on it. I have already replaced the distibutor to an HEI. I recently replaced the mechanical fuel pump. The boat ran kinda crappy at idle with the PCV hoses connected to the flame arrestor and I thought I had some oil blowby from the rings. To get through the summer I ran some half inch water hose out through the bilge and out the stern of the boat. The boat runs pretty well and I have been wakeboarding, kneeboarding, and tubing with it for a few weeks now. I noticed the holeshot was a little weak and once the nose drops on plane it would delay a few potatoes and then the motor would really kick in. I knew it wasn't right and I noticed that the crankcase gas smelled super rich. It wasn't a problem until I broke out my slalom ski and the boat was very slow to pull me out of the water. I am not so sure my PCV problem was oil blowby and might be fuel. I tried to adjust the idle mixture screws which were two turns out. (Which I know is too much) I tried to turn them in until I get an RPM Drop but the RPM never really changed. I noticed that the motor picked up RPM with the mixture screws all the way in (clockwise) and it did not die. I suspect a Power Valve but Richard at SKIDIM told me the new ones are not likely to fail. I did have 2 backfires when I was trying to get the boat running. I just don't wan't to tear the carb apart again if that is not it. When I had the carb apart before I checked the float levels and they were fine. Could the PCV valve hoses being disconnected at the flame arrestor be affecting the mixture. I did spray starting fluid around the and noticed a vacuumn leak beneath the old Rochester wedge. I am going to replace that gasket tommorrow. Anyone have any ideas. I am really regretting this Holley. I should have bought a Rochester or an Edlebrock. Thanks in advance. Pat

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The guy at Holley said the new Power Valves will still blow if your carb backfires. He said the old ones used to blow with the slightest backfire. He said my problem is likely the Power Valve

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