Exhaust replacement
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OK, I'll jump in here.
First, I've never used a mixing elbow like the brown thing. There's a history of them here on the forum getting clogged. Is yours new or is it a used (questionable) unit from eBay?
I have used a riser, and they are fine. Taller is better. The only down side to them is they take a lot of space and require a lot of insulation to protect your boat.
I'd be tempted to try the mixing elbow if it's a new unit. Otherwise I'd build a riser of known performance. Might even think about stainless..
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Thank you
The brown thing is from a used engine I aquired that would not run for longer than 30 min. Perhaps the brown thing was it's problem.
I am trying to reduce back pressure in the exhaust system. Moyer has exhaust setup from catalina diagram that they suggest could be used without a water lift muffler?
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My problem
I am trying to find out why my plugs foul in less than 8 hrs of running. Identical Black sooty fouling on all 4 cyl .
Vacuum at idle is 18-20, and goes to zero at 3/4 throttle. Cyl compression is 90, 95 , 95, 90. Exhaust is blue-gray on start, clean at 165 degrees, timing is at tdoc. I run the slightly hotter plugs and engine starts incredibly well.
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Whether or not a particular exhaust style will work for your boat is dependent on relative elevations of the engine exhaust outlet, available space for a generaous hot section rise and downhill run from the top of the rise to the exhaust thru-hull presumably at the transom at even keel AND heeled under sail. Just because Moyer offers a straight pipe system does not mean it will work for your application.
Studying the Grampian 30 drawings online it appears to me there is enough rise available for a standpipe system on the port side under the cockpit seat. If it were mine that's exactly what I would do. Did we determine your Grampian was a 30?Neil
1977 Catalina 30
San Pedro, California
prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few others
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Al, they are a compromise. Pumping water uphill is always an issue.
I agree with Neil that if you want to incur the expense and have the space in the boat, a stand pipe arrangement would be better.-Shawn
"Holiday" - '89 Alura 35 #109
"Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!)
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I think we agree.
If your engine is in the basement and your exhaust has to go out through the front door, you have two choices.
One is the water lift. Use the exhaust to pump the water.
Second is the riser/mixing can. Long hot pipe, water injection, then out.
Not going to debate the pros/cons of each.
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It isn't pro-con, it is what is physically possible to do.
On my boat using a riser to keep water out of the engine is essentially impossible unless I run a dry exhaust 10 feet long up and around a couple of things into the main cabin and back down.
Like almost every sailboat I have ever seen, I have a riser that fits on the engine feeding a waterlift and then overboard. Some boats have the good fortune to have the space for a standpipe, which is a better system if you can fit it.
Riser at the engine and then overboard is very common on powerboats. There may be a sailboat or two like that, but I have never seen one.Joe Della Barba
Coquina
C&C 35 MK I
Maryland USA
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Originally posted by rveldman1 View PostI am trying to find out why my plugs foul in less than 8 hrs of running. Identical Black sooty fouling on all 4 cyl .
Vacuum at idle is 18-20, and goes to zero at 3/4 throttle. Cyl compression is 90, 95 , 95, 90. Exhaust is blue-gray on start, clean at 165 degrees, timing is at tdoc. I run the slightly hotter plugs and engine starts incredibly well.
As for the waterlift, its just a noise issue. The A4 can be surprisingly loud without a muffler. But it will run fine. You'll just quickly tire of it!
With my waterlift, the engine is so quiet that the blower makes more noise than the engine at idle!Last edited by edwardc; 09-13-2018, 09:41 AM.@(^.^)@ Ed
1977 Pearson P-323 "Dolce Vita"
with rebuilt Atomic-4
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Originally posted by edwardc View PostAs for the waterlift, its just a noise issue. The A4 can be surprisingly loud without a muffler. But it will run fine. You'll just quickly tire of it! With my waterlift, the engine is so quiet that the blower makes more noise than the engine at idle!Neil
1977 Catalina 30
San Pedro, California
prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few others
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