cloudmaster_321

I am having a problem that i have noticed just this year. I will also say that i don't know the original method that mercruiser hooked up the breathers from the valve covers, but mine has a 90 degree elbow off of each cover, goes to a tee, then runs a line up to my eddie marine air intake. I know that i will eventually build up some gunk in those lines from condensation and what not. Maybe i should be taking those lines off from time to time and cleaning them out. Not sure.

Here's what happens. I let the engine warm up for X amount of minutes 3000 rpm's or less. Then I will do a WOT run for about a minute or so. When i look at the engine after that run, i will see oil on the front left side. It does not appear to be coming out of the dipstick. It appears to be coming from the aircleaner, or something under the stock intake plenum. It's really hard to tell and i havn't been able to figure out it's origin. After the engine is heat soaked, it doesn't do it anymore. Just that initial hard run........ About the only things i can think to do is take those lines off and make sure they are clear. Short of that, i'm stumped. Any ideas?? Thanks

Ryan

cloudmaster_321

I took a look at the original parts layout, looks like there is some sort of breather baffle on one side, and a pcv valve on the other. Do both of those lines run up to the stock flame arrester, or just one. What was the stock set-up?

cloudmaster_321

Am i putting too much of a vacumm on the valve covers by having those lines hook directly to the intake assembly?

I see puke tanks for sale all over, what's the theory on that, maybe that's my answer?

cloudmaster_321

Well, i did some work tonight. I took off all my fancy breather hoses, and AN tee i had was plugged. So my theory is until the engine is heat soaked, it was plugged enough that the crankcase pressure was pushing the oil somewhere, yet to be determined. When the engine was hot enough, it was allowing enough ventilation. Not sure, what ya think.

I would still like to get verification that the stock setup only had one valve cover with a pcv valve and hose going to a intake fitting, while the other side had the breather baffle with a hose just butting up to the filter. Can someone please verify this? Thanks.

Griff

Generally the hoses from the valve covers run independently to the flame arrestor without being T'd.

mookymonkey

my origional 502 only had one breather tube going to the intake on the left side. 502 mpi though, not a carb.

cloudmaster_321

mine is an mpi

Ted G

iTrader: (1)

My MPIs have a fitting on the starboard valve cover right below the flame arrestor. It has a short piece of hose that basically butts up against the flame arrestor. It also has a fitting for a hose from the other valve cover to attach, that hose runs under the upper plenum and goes to a 90 degree fitting in the port valve cover. No pcv valve is used, they depend on low pressure at the flame arrestor to draw the fumes into the engine.

cloudmaster_321

I did have the breather with the hose that butted up against the filter. The parts break down shows that on one side like you said, and a pcv valve on the other. I was also told that maybe my oil temp is not sufficient at idle. Was told to look into an oil thermostat, i know nothing about them though.

Ted G

iTrader: (1)

Are you running an engine thermostat?