Reply With QuoteHow was the motor broken in? Did you put synthetic oil in the brand new motor? Who put it together? Any warranty? Is it blowing smoke out the exhaust too? Describe with a little more detail and maybe we could work out a solution.
On a recent outing to the lake I noticed my brand new 460 was blowing oil out of the breather cap its a hardin mariene 460 recently refreshed std bore little bit of a cam also it would run great a about 4300 rpms then the rpms would drop to about 3500 with my foot still in it. It has a 750 vac secondary I think a double pumper would fix some of the problems. Any help whould be great.
How was the motor broken in? Did you put synthetic oil in the brand new motor? Who put it together? Any warranty? Is it blowing smoke out the exhaust too? Describe with a little more detail and maybe we could work out a solution.
Sounds like you have a fuel supply problem to me. Did you change all the fuel filters before running the new motor. Check the tank, all fuel lines, fuel pump, the filter in the carb, etc. A doublepumper/mech. secondary is a good upgrade, but try to fix the problem first.
Actually, that exact same thing used to happen on my 750 double pumper. It turned out that the secondaries were running out of fuel- dirty cross over tube & passages. A rebuild was in order for me.
I agree with mister460- that oil situation sounds a little more serious. I don't know if the RPMs are related to the oil blow-by, but that's generally not good. How much oil? What do your plugs look like?
Not much oil just a little it was broke in running at an idle about 1500 rpms for about 30 min with 10w-40 not synthetic no oil out of the exaust. It has a pcv valve on one valve cover and a breather on the other. New fuel filters and fuel line were installed when the motor was put back in. The tank was flushed at a radiator shop. Both filters stay full of fuel. Also ran boat at about 25 mph for the first 2 hours on the water then the oil was changed and noticed the problems after that.
Also the plugs are just light tan no burnt oil. The motor was put together buy Charlies performance Ford I've got a call into charlie as we speak. He told me when he put it toghther that he would fix any problems but I wanted you fellas to give me an opinion first. thanks mister460
It sounds like a premature blowby .Not very encouraging when you just had the engine done.There's a possibility the rings were installed the wrong way.Try a new PCV anyway,and check if there's a baffle plate under the breather cap inside the valvecover.Hopefully you just need time for your rings to set in?Also I would go up to the 850 Holley marine carb with vac secondary.It has 88 primaries and 94 secondaries.Try it you'll like it as the phrase goes,hehe.You didn't mentioned if your 750 carb was checked or rebuilt? Occasionally the diaphragm [membrane] can fail and is readily available at speedshops.You check it with engine off,throttle wide open and push the rod upwards and see if it settles back nicely to its original position after you let it go.You can change the diaphragm spring rate also.
[This message has been edited by spectras only (edited June 04, 2001).]
[This message has been edited by spectras only (edited June 04, 2001).]
Spectras is right, the rings or just one set of them may have been installed upside down. This would cause alot of combustion blowby, hence oil out the breather. Try checking the power valve on the carb, too. They can blow out with the slightest hiccup of the engine. Was it ran at a constant 25 mph of was the speed varied? Constant speed during break in is BAD. But doesn't sound catastrophic though. Maybe a broken ring or somethin'. Good luck regardless!
Thanks for all the help guys charlie is checking compression. said hed fix any problems not constant 25 average crusing around the lake.
Is it blowing smoke or oil.smoke would indicate blowby.If it is oil what kind of valve covers do you have .if they do not have a baffle in them oil will seep out that was a problem on my boat bought new covers with baffles and the problem went away more common as the rpms increase.
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