Hi, this has been an ongoing problem for as long as i can remember with the boat. If ever the boat starts to vibrate/run rough on idle/only run on 3 cylinders I now go straight to the riser/manifold. two years ago i replaced riser and manifold. Last year it turned out manifold was faulty/leaking and it was replaced under warranty. I now have the same issue.
On the muffs it will idle for ever and a day very smoothly, out in the sea idle idle smooth for 1 or 2 mins then drop a cylinder and run rough. A little rev out of gear clears the roughness. It also does it if we are running at low speed for a length of time, it then bogs down before pulling away, unless we rev it out of gear before pulling away.
Why would this be happening at sea, even in flat conditions but perfectly fine on the drive.
I removed the riser and yup water in manifold again! I have heard of a manifold extension to raise the riser away from the sea. Would this help? But i cannot see how the rubber boot then joins the exhaust to the riser.
Also my boat never had the restrictor plate, I fitted it once and found it leaked even worse so ditched it and went back to one gasket/one joint.
Honestly I think this design of manifold/riser is the worst that could very have been thought up. Both riser and manifold surfaces look better than good what would you guys do, do you think water is coming back down from the sea side , we tested for a blockage in the exhaust, i really don't think there is one, water poured out of both the prop and when we moved the hose back a bit in side the exhaust to came out the exhaust before the leg ( im not sure what that is called)
Thanks in advance for guidance
On the muffs it will idle for ever and a day very smoothly, out in the sea idle idle smooth for 1 or 2 mins then drop a cylinder and run rough. A little rev out of gear clears the roughness. It also does it if we are running at low speed for a length of time, it then bogs down before pulling away, unless we rev it out of gear before pulling away.
Why would this be happening at sea, even in flat conditions but perfectly fine on the drive.
I removed the riser and yup water in manifold again! I have heard of a manifold extension to raise the riser away from the sea. Would this help? But i cannot see how the rubber boot then joins the exhaust to the riser.
Also my boat never had the restrictor plate, I fitted it once and found it leaked even worse so ditched it and went back to one gasket/one joint.
Honestly I think this design of manifold/riser is the worst that could very have been thought up. Both riser and manifold surfaces look better than good what would you guys do, do you think water is coming back down from the sea side , we tested for a blockage in the exhaust, i really don't think there is one, water poured out of both the prop and when we moved the hose back a bit in side the exhaust to came out the exhaust before the leg ( im not sure what that is called)
Thanks in advance for guidance
