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scttmzr posted a topic in Centurion Boats General DiscussionFrom what I've read online it seems that my 2005 Enzo SV230 has all the symptoms of a failed Idle Air Valve (IAV). It stumbles around idle coming out of gear quite often and sometimes even dies, and the only way to get the engine to start when its hot is to give it neutral throttle. After some reading online I ordered the Standard Motor Products AC423 Idle Air Control Valve of Amazon for $40 (In comparison to the $178 for the OEM Mercruiser 866326) which is supposed to be a direct replacement. Multiple people on Amazon said it worked perfect on their Mercruiser 350 Mag MPI so I figured it should work on mine! Of course when I received the part and went to install it I found a couple things that I'm not so sure about: The original part I removed (assuming it is OEM) does not appear to have a pin and spring in it that the new replacement part has. Anyone know the function of this, or if it is of any concern? The replacement part came with a small rubber gasket that is definitely not correct for this application; it appears as though it should be used in an application that has a machined groove more like an o-ring would have. After searching for the correct gasket online, all I seem to find pictures of is a simple thin sheet style gasket that is cut to the profile of the valve. The gasket I removed from the boat was pretty thick and is overmolded on a mesh screen material. I'm wondering why this screen would be necessary? Does it keep the foam filter (see question #3) from entering the valve? When I searched for the OEM replacement gasket I found that the original P/N 865168 was superseded by 866326... The notable thing here is that the part description of the gasket also changed from "Gasket, Flame Arrestor" to just plain "Gasket". Did they remove the screen from it for the new part? Once I removed the gasket I found a small foam filter (Mercruiser P/N 865266) in the bottom port of the intake air valve adapter body. Anyone know the function of this filter? Any air that is in the intake manifold has already passed through a much finer air filter so I don't understand it's purpose. I ask all these questions because I'm trying to get the boat water ready in time for the 4th, and I'm struggling to find the OEM gasket readily available.
knotguilty posted a topic in Centurion Boat Maintenance, Performance, TroubleshootingThis has been the year of "extended maintenance" for my 2005 Avy. The real trouble started with a stuck fuel injector earlier this year. I limped the boat back to the dock (20 minutes to go ~3 miles) with white smoke and un-burnt fuel coming from the exhaust. The computer was throwing a injector group #2 stuck open error. I replaced all of the injectors, inline fuel filter and water separator. I also changed the oil and oil filter because the oil had 2 quarts of fuel in it. The next time I took the boat out, the boat started and 2-3 seconds later the engine died. The only way the boat would start was to crack open the throttle but once it started and warmed up it ran but would run rough at idle. After doing some research I replaced the IAC ( and the muffler that goes with it. The muffler was clogged up before I replaced it. Since then the boat would start with some hesitation but it would run very rich and unstable at idle. Anything above idle the boat runs great. I have hooked up the Rinda computer and tried doing a IAC test. The RPM does not change when I try to open and close the valve. (RPM bounces around between 580-650) I have also tried cycling the valve without the engine running and the rod does not move. However, the valve will make a buzzing noise around +30%. I put the old valve back on and it acts just like the new one. I have bought 2 IACs and between the old one and the 2 new ones they all act the same. The 2 new valves are a Standard AC423 and a BWD 50558. This is what the Mercruiser 862998 cross referenced to. Interestingly enough after running around 2000 RPM for 15 minutes or so the IAC Duty Cycle reads ~30% when I first go back to idle. The boat runs pretty good here. However, the longer I sit at idle the more the IAC Duty Cycle will creep back to 99.9% and the boat will run rougher and rougher with a strong smell of gas and black exhaust. Does anyone have any experience with trouble shooting an IAC? Shouldn't the Duty cycle sit a close to 30%? Shouldn't you be able to move the IAC with the Rinda back to a point where the engine pretty much starves of air at ~-90%? I'm getting a bit concerned that I'm looking at a new ECM...Any thoughts on where to go from here? I have already checked the resistance of the valves (12.5 ohms). I also checked the resistance back to the ECM and that checked out. The ECM will send a warning signal (2 beeps) only when the IAC is disconnected. The harness is reading battery voltage (12.4 Volts) with the engine off.
mrredfolks posted a topic in Centurion Boat Maintenance, Performance, TroubleshootingIm starting a new thread on this topic because i have seen several people post about this but no one has ever came back and said YES this is what fixed my problem. I have a 07 Avy 5.7 liter black scorpion Not showing any codes on the computer One day the boat died after surfing. Start back up no problem. Does it again when returning to idle position . So what i have found is that the boat will die after going from a throttled up position back to neutral. Here is a list of things already done. There has been some improvement but still will die. ESPECIALLY when throttling up and going back down to neutral. (like when you would be putting the boat on the trailer) AND i have noticed that it starts to fall off as soon as the V-DRIVE LIGHT comes ON. If i have the boat in gear but under the 1200 rpm so the light stays on i can go back and forth from neutral, but as soon as i go over the 1200 rpm and back it will die. Diagnosed with low fuel pressure 34-35 psi Changed low pressure fuel pump and high-pressure fuel pump and fuel pump regulator Running about 40 psi now. THere was improvement, but the more it runs seems like the worse it gets The IAC valve was replaced at the beginning of the year, and it shows it running when hooked up to the computer. I THINK this may not be working properly. (bad part?) Does anyone have any thoughts on this I read that a blown intake gasket or a throttle body gasket could produce same symptoms. Distributer cap and rotor look fine. Also replaced at the beginning of the year. After taking off the Throttle body there was a lot of oil present. Could this be due bad PCV valves these have not been replaced. Looked at vacuum hoses could not see anything out of the ordinary. I feel like it is a air problem at this point in time. Since all of the fuel system has been replaced. I am thinking either blown gaskets or some type of vacuum leak? MAP Sensor? Throttle Position sensor? Please Help!!!!