won't start after a windy sail

[Fstued]

MY engine runs well when it runs but after a good windy sail when the boat gets on it ear for bit the engine won't start. It will crank over but wont fire. I was told water is getting up into the cylinders via the exhaust. I have a flab on the exhaust to stop back flow but I guess it isn't working like it should . If I crank for a while 5 or 10 min it may fire but at sea that will kill the batteries .
Are there better flappers or something to put in the line to stop the problem. Or maybe thats not that problem. I'll sail back into the slip if it wont start which can be dicey. Come down the next day and it fires right up. Even get back to the dock and plug in and it will fire after 10 or 15min of cranking.
Looking for suggestions Thanks

[joe_db]

Photos and/or a drawing of your exhaust system would help. A flap on the transom fitting will never be good enough to keep water out. I have BTDT and had to do some hose arranging to keep water out.

[JOHN COOKSON]

Go for a rambunctious sail then try to start the engine for a couple of minutes. If it doesn't start pull the spark plugs. Water will sort of bead and glisten.
A long shot: Be sure the choke is all the way closed when you think it is. The cable may be flopping around when the boat heels.
Is the hard starting after sailing something new or has it always done that as long as you have owned the boat? Is there a siphon break somewhere in the exhaust system that may be sticking which would result in water siphoning into the engine while you are sailing?

TRUE GRIT

Edit: Remember short 8 or 9 seconds on the cranking bursts with an equal length of time between tries. This will keep the starter motor cooler and give the battery a chance to snap back a bit.

[Mermaidquest]

Remember that lot's of cranking can inundate your muffler with sea water adding to the problem.

[Al Schober]

Used to sail with a guy with a Catalina 27. His solution was to put a rubber plug into the exhaust at the transom. Starting the engine would blow out the plug. A string kept it from getting away.
Of course, this doesn't correct any basic fault in the exhaust design..

[Wrsteinesq]

What's the thinking on a check valve of some sort? I know that many think they are a poor practice in bilge pumps, because they can clog; but I'd certainly think that anything coming out of the exhaust would be pretty free from debris.

I'm trying to install a standpipe exhaust but don't have an awful lot of drop between the standpipe outlet and the exhaust thru hull in the transom. It's not hard to picture following seas, etc., shoving water back up a not-far-from-level exhaust line. About 7' of exhaust line holds about three quarts, then another quart or two and my standpipe would fill, then we're into the hydrolock I want to avoid.

I have an old Edson check valve here, but it uses a pretty small floating ball to clog a seat of about 5/8". In effect it's restricting a 1-1/2" hose to 5/8" and that doesn't seem good. I'm thinking about some sort of duckbill valve. They seem to open wider with more flow. Any reports on the failure mode of duckbill valves? Do the lips stick together and prevent flow? Is exhaust pressure enough to ensure they'd open? Is mixed exhaust gas and water cool enough for them, especially if placed at the end of the line, nearest the transom thru hull fitting? There's plenty of plastic waterlifts out there, and if they fail that's a good way to flood the boat, but if a duckbill failed in any other way than sealing itself, what's the harm?

[ndutton]

The Catalina 30 has a 1¼" horizontal swing check valve in the wet exhaust hose at its highest point as standard equipment. I believe it has more to do with normal backwash than surge up the wazoo due to the considerable length of the run, like nearly 20 feet. I know of some with the external flapper too.

I second Joe's request for pictures and/or drawings of the exhaust system before we head down the path of recommending modifications. I'm not completely convinced (yet) that this is an exhaust problem.

[Bratina]

When was the last time that the tank was cleaned and / or checked for water and crud? It's possible that water is being sloshed around in the tank and being drawn up into the fuel hose when you crank after a rambunctious sail. What fuel/water separator do you have?

When I bought my boat, the engine wouldn't start. I poured my Sierra filter out into a glass jar and it was 10% fuel, 90% water.

[Fstued]

Just put a new filter on BUt I'll take it off and see what comes out. Thanks

[Fstued]

After reading a bunch of solutions and a thorough exam of the exhaust I am thing the anti syphon valve might be the culprit. Also there is no high point between the water lift muffler and the exhaust.
I'll try putting a new exhaust hose in between the thru hull and the manifold with the proper lift in it.

[Administrator]

Lessons learned the hard way:

A filter may or may not include a water separation capability.

100% water looks just like 100% fuel.

Turbulent conditions may introduce water into the engine at the worst possible time.

Engines don't run well on water.

DAMHIK.

Bill

[JOHN COOKSON]

Also there is no high point between the water lift muffler and the exhaust.
.

It may be worst than you are observing. Sail boats have a raised area at the end of the stern to varying degrees. This is easy to observe when the boat is upright and not underway. However when underway, power or sail, the end of the stern will squat and be slightly under the water or at water level. Be sure to take this into account if you redesign your exhaust system.

TRUE GRIT

[Peter]

"Go for a rambunctious sail then try to start the engine for a couple of minutes. If it doesn't start pull the spark plugs. Water will sort of bead and glisten."

Have you done this diagnostic? It seems to me you have two potential problems - water in the exhaust or dirty fuel. I think it would be useful to try to pin down which one it is before embarking on any repairs.

Dirty fuel - I had a brand new filter clog up on me in very little time due to dirty fuel. A fuel pressure gauge - $20 and easy to install - was instrumental in the diagnosis.

Peter