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leiniemann

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"I have twin 5.7L, 270HP, 1978

"I have twin 5.7L, 270HP, 1978 Crusader motor. RH rotation has about 1200 hrs. and LH has about 400 hrs. In the last six weeks or so the RH motor has started using oil at the rate of about quart in a 30-45 cruse, running at 3500 RPM’s. There was a slit valve cover gasket leak, but I have replaced that. There are no major oil leaks that I have seen. I checked compression, and it ranges from 128 to 130 on one side of the motor (which was the last side checked and it had cooled a bit) and 130 to 140 on the other. Compression numbers sound fine to me. I did have an issue with water in the fuel at one point this summer, but after I emptied the fuel and water out of the filter it ran fine. About 75% of the time it is run at 1500-1800 RPM’s, the rest of the time I do not exceed 3500 RPM’s. Any suggestions as to what to look for are appreciated. Owners manual calls for 10W-40 and that is what I have always run, this is the third year I have had the boat.

Thanks"
 
"Pull the plugs and look for a

"Pull the plugs and look for any that are darker in color. If so, you might have a bad valve seal on that cylinder(s)that's sucking in oil. (Can be replaced, in place, for not too much $$$)

Jeff"
 
"Jeff you say it can be replac

"Jeff you say it can be replaced, in place. Do you mean just the head does not need to come off. If so how do you do this and replace the valve springs and keeper, or is the seal a split seal?

Steve"
 
"You put compressed air in the

"You put compressed air in the plug hole to hold the valve closed, then pull the keepers and springs. Put new a seal in place, then reassemble. Easy to do.

Jeff"
 
"I put in new plugs, I have at

"I put in new plugs, I have attached an image of the old plugs. They all look quite dark. Would you say all the valve seals are bad? At this point, would it make sense to pull the heads and do a valve job?

114266.jpg
old plugs"">

Steve"
 
"The plot thickens. We went ou

"The plot thickens. We went out yesterday and the first leg of our trip was a slow 1500 rpm ride, after which I checked oil and it did not appear to have used any. On the return leg we ran at 3200 rpm’s, after which I checked oil and again, it did not appear to have used any. The only thing that changed was new plugs. When I changed plugs I checked the PVC valve, and it was stuck, I tapped it a few times, it loosened up and would rattle. Could the stuck valve cause the oil usage? Any thoughts?

Thanks
Steve"
 
"Yes
It causes pressure in th

"Yes
It causes pressure in the crank case, forcing oil passed seals and rings. Replace it."
 
Those plugs are running way to

Those plugs are running way too cold. Mine are are a very light grey color.

Jeff
 
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