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  #1   IP: 108.185.116.22
Old 01-13-2023, 12:02 PM
ejay ejay is offline
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Possible fuel excess?

I have had issues with my A4 not starting in the past which have been resolved with removing spark plugs, and drying out the cylinders. I have blamed water incursion in the past, but I did not put my tongue on the spark plug to see if there was a salt water taste. I wonder if excessive fuel could "flood" the engine before it starts?

A previous owner installed some creative fuel pump wiring so that the fuel pump will turn on before ignition. He told me that I had to do this to "prime" the engine, but I wonder if running the fuel pump before ignition could foul the plugs with excess fuel and prevent starting?


Thanks!

ej
78 C30
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  #2   IP: 162.245.50.205
Old 01-13-2023, 01:04 PM
Dave Neptune Dave Neptune is online now
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The A-4 has an updraft carburetor which sits well below the "intake runners" in the manifold. The "excess" fuel if there is any before cranking would run out the carb and not get into the cylinders. After cranking and no start with the choke engaged is about the only way the plugs can get wet from fuel.

Do you shut the water valve off at the thru hull when done with the engine? If you do is is time for a pressure check of the intake manifold, not difficult with parts from the hardware store. If the manifold is good do a compression check which is easier than pressure checking the "block".

Dave Neptune
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  #3   IP: 76.176.224.167
Old 01-13-2023, 11:22 PM
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We should know what the liquid is, fuel or water, to be able to resolve this. The direction of Dave's post doubts it's fuel and more likely water. Easy enough to check with a taste test. Speaking of tests, it would also be good to know the general condition of the engine and exhaust configuration and condition. A water jacket pressure test on both the manifold and block separately and a compression test would tell us a bunch. A detailed description and pictures of the exhaust system would be very helpful too.

I have a 1977 Catalina 30 with probably the smallest volume waterlift muffler fitted anywhere, the Centek 150002 top in - top out, an anti-siphon vented loop as opposed to an anti-siphon valve, a swing check valve at the high point of the exhaust run to the transom and an external flapper at the outlet with never - and I mean never - a water incursion.
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1977 Catalina 30
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prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few others
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  #4   IP: 12.163.75.202
Old 01-16-2023, 01:32 PM
ejay ejay is offline
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Here is the pic of the hot gas exhaust going to the muffler. You can see there is no rise at all, given the limited space in the C30, which has always made me worry about the water incursion during sailing. However, the instances where the engine would not start have not been during or after excessive heeling, but after the boat has sat quietly in a marina.

I had to replace the previous exhaust run that was just like it, due to a catastrophic failure during a trip. I insulated the pipe after this picture.
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Old 01-16-2023, 02:07 PM
Dave Neptune Dave Neptune is online now
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Cool

Granted that is not much rise. I had the same problem with height.

Do you have an anti siphon valve? Many with C-30's and E-35MKII's have eliminated them as getting enough "height" to make them function well is problematic. I eliminated mine and ran a bleed to a cockpit drain and Neil eliminated his too I believe but I'm not sure where he connected his. I'm sure Neil will chime in with that info.

If the engine is running well once running I would first check the integrity of the manifold as an internal pin hole leak would take a long time to get much water into the manifold like when sitting for a long time with the engine off. If the A-S valve is sticking it would not take long to get water into the cylinders.

If the manifold checks good a compression check may yield some answers.

Dave Neptune
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Old 01-16-2023, 03:15 PM
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The vent on my loop is connected to the sink drain plumbing inside the galley cabinet. Attaching it there ensures it's connected above the waterline, the waterline being roughly equal to the bottom of the galley cabinet on a Catalina 30. A better place in my opinion would be into the side wall of the galley sink although drilling a hole into the stainless sink would be a chore. Of course if going to a vented loop and plumbing it into the sink drain, the sink drain thru-hull must be open during engine operation.

Thanks for the exhaust hot section picture ej. I'm not seeing anything amiss although double clamping would make it more secure and therefore safer.

I'd still like to confirm what the liquid observed on the spark plugs actually is. We are thinking it's probably water but only you can tell us for sure. And I completely agree with Dave, manifold pressure test is next.

Other info:
On another forum (that's actually more like a blog) ej asked if anyone had a muffler drain system to evacuate the residual water in the muffler after shutdown. Well, I do. The thread discussing it is found here. During its development I actually measured the residual water volume after shutdown and surprisingly it wasn't much at all, like barely a quart. Several measurements were made at different engine RPMs at shutdown but the results were consistent. I'm not suggesting such a drain system is necessary or even recommended because as I mentioned earlier, I never had a water incursion prior to its installation. I have it installed now because:
  1. The Catalina 30 exhaust system design is frighteningly marginal
  2. It's one more tier of prevention
  3. I'm a tinkerer
  4. What good does developing a drain do if it's left on the workbench?
  5. A solution in search of a problem maybe?
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1977 Catalina 30
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prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few others

Last edited by ndutton; 01-16-2023 at 03:51 PM.
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