knotguilty

I love the roar of my boat when it is idling but I didn't care for the overly loud exhaust when i was cruising down the lake. By the end of the day my crew and i were all def between the music and the exhaust. I have seen many posts on this topic but I didn't see one this inexpensive so i figured i would share. I installed these in my 4" exhaust tubes going from the Sideswipe valve to the exhaust tip. It took me about 30 minutes per side and cost me ~$100 with shipping. I saw no loss in power the boat is somewhat quieter going down the lake but the real magic happens when I switch my exhaust to one side. It almost goes silent. A bit like captains call. I saw almost no reduction in idle sound with both exhaust ports open. Perfect for me. Here are the silencers I installed: http://www.cpperformance.com/p-12622-4-slip-in-silencer.aspx Here are some pictures of my install. Basically came down to drilling one hole in the exhaust tube to hold the silencer in place. Hardest part was taking the tubes out. Came down to brute strength and ignorance.

I have the setup that you describe in my '05 Avy. It works fine. The only issue I have found is the tank above the seat drains into the lower tank slower that the pump can pump out. Just means that I check that the center tank is empty before I pull out.

Looks great! What kind of thread did you use?

This 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.

The belief now is that the fuel pressure regulator drove the injectors to force open. I cleaned them all with injector cleaner and did a balance test before hitting the lake. All good so far.

Problem solved! I did a balance check on my new injectors (500 ms and 20 cycles) fuel pressure dropped 9-10psi. I put the old injectors back in and 8 psi drop. 20% more fuel from the new injectors. Looks like China replacement injectors are not the place to save some dough. I left the old injectors in and went out on the boat all day Sunday. She purred like a mountain lion! No black streak on the side of the boat either!

Video of my vacuum gauge and RPM on the scan tool. https://youtu.be/XqJKj1Keu5g

I replaced the fuel pressure regulator in the cool fuel box and the fuel pressure looks steady now but is still running high around 38 psi. The idle is still rough, sounds a bit like a Harley in the water. Sounds like "potato potato potato". The exhaust still smells really rich and I get a black layer of soot like stuff all over the hull near the exhausts (Sideswipe). Vacuum is still running low 12 inhg. Which may explain the high fuel pressure and rich idle. Compression looks good. I can't explain the low vacuum. I've measured it straight at the intake manifold and still low. I have a 555 ECM so timing should be good but I checked it with the scan tool and it is bouncing all over at idle. Rpm is also bouncing between 575 and 630. Does anyone know where the ECM gets RPM? Cam position sensor? One more note, I checked the duty cycle at the IAC. The computer and the duty cycle gauge read the same. I tried 2 new IACs and they reacted the same. They didn't move when not on the engine but I have to assume the airflow helps push the actuator.

I replaced the fuel pressure regulator in the cool fuel box and the fuel pressure looks steady now but is still running high around 38 psi. The idle is still rough, sounds a bit like a Harley in the water. Sounds like "potato potato potato". The exhaust still smells really rich and I get a black layer of soot like stuff all over the hull near the exhausts (Sideswipe). Vacuum is still running low 12 inhg. Which may explain the high fuel pressure and rich idle. Compression looks good. I can't explain the low vacuum. I've measured it straight at the intake manifold and still low. I have a 555 ECM so timing should be good but I checked it with the scan tool and it is bouncing all over at idle. Rpm is also bouncing between 575 and 630. Does anyone know where the ECM gets RPM? Cam position sensor? One more note, I checked the duty cycle at the IAC. The computer and the duty cycle gauge read the same. I tried 2 new IACs and they reacted the same. They didn't move when not on the engine but I have to assume the airflow helps push the actuator.

Are you using non detergent Oil? I made the mistake of putting a little normal oil in and the oil foamed up on me and caused the light to go off at higher RPMs. Took 2 complete oil changes to get about 1/4 quart of "detergent oil" out.

So back to the fuel pressure. Sounds like replace the fuel regulator on the cooler first and go from there?

Yes, that is my engine. Made the videos last night. Not sure what you mean by cross fire distributor cap. The cap is not Murcruiser. It is a standard 350 small block rotor and cap.

I tested the vacuum as well tonight. Runs between 10-12 hg in. Sounds low but my plugs are covered in soot so I'm guessing my valve seals are too. Check out these videos: https://youtu.be/eQfp6N1H00k https://youtu.be/i7QScZVQ2hg

Tommy, Thanks for testing. That helps. Was the fuel pressure steady? Sent from my iPhone using Tapatalk

I have a Rinda. I paid almost $400 for it 4 years ago. I believe that is the cheapest option to check the codes on a Merc. At least the cheapest I have found.

I checked my fuel pressure. When I turn the key the pressure is rock solid at 43PSI until the pump goes off. Once the pump stops and before I start the boat the fuel pressure drops to 38PSI. Once i start the boat the pressure bounces between 36 and 43PSI at idle. I tested this in the driveway so I didn't go to higher RPMs. Is it normal for the fuel pressure to bounce erratically at idle? I'm thinking I may need a new regulator. The one on the fuel cooler. Apparently the regulator on the rail is a dummy but can still go bad according to the manual. Yeah for extra parts! As far as the IAC and the computer all is good there. I checked the DC and AC volts and everything checked out. Even though the control is a square wave duty cycle RMS voltage tells me the control is sending the right signal. I measured the voltage from the Black and Green wire (IAC grounded control) and the sky post (best ground I could find). Results below for reference: %Duty Cycle (Rinda) AC(V) DC(V) 100 0.0 0.0 90 2.3 1.15 80 4.4 2.26 70 6.6 3.35 60 8.7 4.46 50 10.8 5.54 40 12.8 6.64 30 14.7 7.27 20 16.6 8.81 10 18.5 9.87 0 19.9 10.74 Before engine start the valve was controlled to 0% and idle immediately after start was at 100%.

Checking the pressure on a good running boat would be helpful. Also if anyone has a Rinda and wouldn't mind running a IAC test and let me know how much the RPMs change. Mind does not change at all which has me concerned. My fuel pressure gauge comes in today so I should know more this evening.

This is the one I have on order. Actron CP7818 Fuel Pressure Tester Kit https://www.amazon.com/dp/B0006V2BI2/ref=cm_sw_r_cp_api_Y3xAxb470PGXP

Nnoia05, There are 2 fuel pressure regulators. One on the lower starboard side on top of the fuel cooler and one on the fuel rail where the fuel comes in on top of the engine. The fuel regulator on the fuel cooler is set to 43 PSI. Does anyone know what the one on the fuel rail is set to?

When I pulled the plugs to do the compression check the plugs were black. Lots of carbon, indicating once again she is running rich. Not surprising but worth mentioning. As far as the 2 qts of gas I'm thinking it was not just one injector. This ECM controls the injectors in 2 blocks. I think one block shorted out and opened up 4 injectors. In 2 miles I went through 15 gallons of gas. Yeah, I didn't think that was possible either.

I forgot, I replaced the cap and rotor as well when the rough idle started. Checked the compression tonight; 170 PSI on all cylinders +/- a few PSI. Looked good. I borrowed a fuel pressure gauge but I don't trust the gauge. Said I had less than 5 PSI. I had the boat doing 40MPH with 2 people and no hesitation this weekend. I'm thinking high pressure (45+) not low. I have a fuel pressure gauge on the way from Amazon.

Hey guys, Thanks to all the help from this topic I was able to make a wind dam as well. Thought I would share. I'm pretty proud of the results. I had a lot help from a local machine shop. Made from 1/2 acrylic and covered with reflective vinyl.

I had my Perfect Pass stepper motor seize up on me a few months back. I called up the Perfect Pass guys and they sent me directions on how to take the motor apart and clean it. It is all back together good as new and works fine now. There are a few threads on here about how to clean the stepper motor as well. While I was on the phone with Perfect Pass tech, they mentioned that they have noticed a lot more of these motors are seizing on boats used for surfing. Something about using extra ballast, water in the bilge, serpentine belt splashing water here and there... blah, blah, blah! I got the theory immediately and thought a few others on here might have a similar phenomenon happening on their boat. After talking to tech for a bit the solution was a simple 30 minute box. I used some sheet metal flashing and pop rivets and made this cool little box. I rolled over the edges that come in contact with my rubber exhaust and I cut out a small rectangular hole for the throttle cable. A couple of cable ties to hold the box on and now my stepper motor is now protected from splashes. I sealed the motor up real good when I cleaned it but I figure a little extra protection is never bad.

I finished up my plate install a few weeks back. Worlds of difference both loaded with ballast making waves and cruising down the lake. I'm not a goofy rider but I wanted an actuated plate and figured that the asymmetrical plate was the way to go if I was going to do it. I have about 4" of travel up and 2" of travel down. I decided to go with a single actuator closer to the port side because of the ballast intakes. I don't want to go with the Lenco control module and am afraid that the actuators may go out of sync or god forbid one of the actuators failed and locked in place while the other still moved. I used 3/16" 6061 T6 (Fully aged) aluminum. I had to use a 60 ton hydraulic brake to bend the plate after attempting on 2 manuals. I have no fear of the plate bending under load and I found it on e-bay for just over $50 with shipping. The guy who helped me bend the plate built his own aircraft so riveting the plate to the hinge was the only way to go and everything is flat other than the pan head screws that came with the actuator. I went with a 1581A911 hinge from McMaster-Carr. For wiring I used the Teleflex switch with 4 standard single pole relays. 2 for up and 2 for down. The 4 relays are not as clean as only having 2 double pole relays but I only paid $15 for 5 with harnesses that lock together on Amazon. In the end everything looks clean and is tucked nicely behind my switch panel. Everything together I paid $340 and am very pleased. My port wave is taller now and with a couple of taps I can make a longer wave for me and the steeper shorter wave for the wife without stopping to fill or dump bags. I can also bring my nose down at slower speeds and stop that pesky porpoising at higher speeds making for a more comfortable ride while I'm cruising. Second best mod I have done. Right after upgrading my stock ballast. Thanks for all the help from everyone here!

I'm looking to install something similar. Has someone installed these springs that is willing to post a pic?