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What might cause this?

E

Eaton Beiver

Member
A 440 that's been running fine this season, 30 hours of perfect running. No over heating (& confirmed with a infra-red temp gun), no steam, no water in oil, tan colored plugs. no problems.

I go to take the 2'nd run of the day, and it wont crank. I find water on all spark plugs, and water comes out of all cylinders when I wheel it over.

I check compression, and it's 150 in all cylinders. I find no water in oil, either.

I keep the boat in a hoist, so there is no way it took on water thru exhaust. It was 2 feet out of the water before this happened.

And with water coming from both sides of the engine (& good compression) it's hard to see this being a blown head gasket.

And ideas what might cause it?
 
...."I keep the boat in a hoist, so there is no way it took on water thru exhaust. It was 2 feet out of the water before this happened. "

Au contraire, mon aime! (Translation: The water in the elbows and risers ran down into the exhaust ports.) And it doesn't take much water to mess things up.

Before you pull the exhaust system off, or rip down the motor, you need to find out what happened to a previously good running motor. You say the boat is kept on a lift. Is it possible that the bow was tilted down during lifting? It doesn't take much--especially if you have a long exhaust system--for water to run forward and flood your motor.

If you think this MIGHT be possible, pull the spark plugs, wheel her over good to get the water out, then fire it up and take her for a spin. Next, let it sit--in the water--overnight before trying to start it next morning. And keep your fingers crossed!

Jeff

Jeff
 
I fogged all cyls with fogging oil, and it did start. Idled and reved up OK. I let it sit (only had an hr or so) and then pulled plugs and they looked dry.

I also double checked the lift, and boat sits level in the lift. The boat does have long pipes, but they are well sloped out the back, when boat is on hoist. (..was actually hoping this might be it, hadn't thought of that one...)

Still a mystery. Just like that, water everywhere.
 
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The flappers only keep MORE water out. What's already in the exhaust is enough to slop over and enter the risers and cylinders. Also, you need to wait overnight to see if you have the usual water leak from the exhaust.

Jeff

PS: If what I'm thinking is happening here, could you adjust the cradle of your lift to tilt the boat stern low as it is lifted?
 
I had leaking exhaust manifolds last season, and they were both replaced with new ones last year. Unless they both failed simultaneously (after 1/2 a season in fresh water....), it's hard to see them as the root cause. But you got me thinking about the lift.... I do have a bow stop, and ocassionally I bump it if I have to come in a little fast. (Like, if it's windy and I need a little speed for better steerage). Possibly the water in the exhaust sloshed forward when I bumped the bow stop, and then I shut her down with water past the risers. The 440 in mine has log style manifolds on not much height in terms of risers. It does not have those big swivel type deals.
 
Are you by any chance in the habbit of throttling up and back quickly just before you shut off the engine? Also, I don't recall if this applies to 440s but some intake manifolds are problematic around the T-stat location. Corrosion pops a hole into the nearest port. Does anyone know if there is a water pasage next to the crossover on the intake manifold?
 
You need to TEST and see if the water is getting in from a gasket leak or etc.

Run the motor good, then let it sit overnight a dock or at anchor--not on the hoist. Next morning, pull the coil wire so it can't start and crank it over. If it does the RRRR--hesitate-RRRhesitate-RRR thing, there's water getting in. If not, then the hoist or ?? is causing this.

Jeff
 
Weekend Update: I changed the oil & double checked compression. No water found in oil, and compression was 130 x 8. Starts and runs fine. Pulled wakeboarders all weekend. No water in oil after 5 run hours this weekend. Dry spark plugs, too. Root Cause still a bit of mystery, but it must have come up the exhaust pipe somehow. I do notice the exhaust manifolds on that boat ('71 Century Coronado) are only 1 foot above water line, with no elbow/swivel deal. Just manifolds, straight out to 6 foot long pipes. I guess it's possible to slosh water up to the engine if you bump against the bow stop. Who knew?..... Boating is a lesson every trip.
 
Do you have exhaust shutters in the exhaust system or flaps at the transom to prevent a swell from creeping up to the engine?
 
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