Call me if you have time. Lynn 419-654-1222

Does anyone know what the solution was to both of the motors not running over 4,000 RPM? I have a 2007 382 Fastech with 700 SCI's and they will not run over 4,000 RPM (it used to run up to 5,200).

Thank you very much.

They pretty much have to be in a reduced power/guardian mode.

Thank you for your reply. While running the boat, my mechanic was plugged into one of the motors and it was not in guardian mode. Any further thoughts?

Thank you.

Are the coil packs original?

My money is on a bad coil pack. Do the motors idle at the same rpm? Sound the same at idle? Check to get a spark tester and check spark on all 8.

Its been awhile since I've looked at a 700 but with individual coil per cylinder, you can unplug (& plug back in!) the ECM side of each coil one by one with the engine running and find which cylinder isn't firing whether it be from an injector or coil. Those engines run so smoothly, you'll be able to feel them stumble when a firing cylinder is unplugged. An easy test to check cylinders for fire. As others have stated, the next check would be the bypass valve in the supercharger. If you have a boost gauge on the dash, you'll be able to rule that out, though.

Both motors run very smooth and idle at the exact same speed. Both motors will only rev to 4,000. While it is possible that it is a bad coil (coil packs are original), what are the chances that both motors experienced a coil failure at the exact same time?

At 4,000 the motors sound and run great. There is no mis-fire or hesitation.

Thanks.

I am having the same issue with a single 600 SCI and my boat is in the shop. Mercury has advised to check fuel pressure and clean and replace fuel filters. Now that that has been done with same results of only 4000 rpm and 70 mph they advised them to replace boost controller. I think that it is a coil pack that is breaking up even tho i don't think I feel a misfire. Can't check the coils loaded and at 4000 rpm unless the mechanic wants a wild ride under my engine hatch, which he said he would consider doing if needed. I told the shop about the comments on here being a faulty coil pack so I will let you know what he finds. The shop has 2 boats in for service with the same problem. My boat is a 08 Nordic Lightning and has the 555 PCM. No codes and no alarms.

You’d probably be surprised how smooth they sound when they’re running down one cylinder. But yea it’s be very odd for it to happen on both motors at the same time. I’d still check spark.