1999 4.3L...

[DanOnTheBoat]

Hello, so I bought a boat... its a pretty nice 1999 bayliner 1850ss with a 4.3L Vortec in it. Last owner owned it for about 13 years and always maintained it, always winterized it, etc... the boat runs great, the owner fired it up and it ran really well. Was holding very steady 600-700rpms on a cold engine. The owner said he hasn't used the boat much in the past few years. The boat was stored under an open shelter all the time with no covers on, at a lake house. Can condensation from temperature swings, weather and water get into the oil to make it look slightly milky? Its not creamy or milky(cappuccino) I checked the block no cracks nothing like that.... oil cap looks clean, also top inside of engine looks clean. Im honestly worried and hoping its just condensation in the oil... has anyone had this issue?

 

[DanOnTheBoat]

Forgot to mention, I have the batwing style manifolds. Could they be the issue of water going to oil? I heard some things about them and how they aren't the greatest... Engine runs flawlessly, starts right up with no hiccups and idles really well at a steady 600-700rpm on a cold engine.

 

[nola mike]

Yes it can. I'd run it at operational temp for a while and see what happens

 

[Scott Danforth]

yes, condensation under the valve covers is common until you get the oil over 212 degrees to boil out the moisture

swap the block-killer manifolds ASAP

 

[DanOnTheBoat]

Thanks for the replies, one thing I noticed is that before and after running the engine on muffs, the oil actually stayed looking the same and pretty clean. It only seemed to look milkier after sitting untouched for about 4–5 days afterwards...

Also, what are the “good” replacement manifold setups for these 4.3s? Are other manifolds basically a direct bolt-on conversion from the old batwing manifolds?

 

[Lou C]

The condensation can definitely happen depending on weather conditions like humidity and temperature, and idling it on the water hose doesn't build enough heat to boil out the moisture.
Barr Marine makes an aftermarket conversion kit for those batwings, IIRC. The problem with not changing them is you'll never know when exactly they are about to fail on you. I had the same design on my OMC Cobra but never had that happen, eventually they became NLA so I converted them over to the later 2 piece design system using the Barr aftermarket 2 piece units and Volvo Penta 90* down pipes and rubber hoses. When I did it, back in '17 it cost about $1400 for parts, not sure what the prices are today.

 

[Scott Danforth]

yes, there are complete kits to replace your batwings with the newer style

 

[Lou C]

https://www.marineengine.com/newparts/part_details.php?pnum=BARMC-KT-V643CONV

About the same price I paid, for my conversion, and I found Barr quality to be pretty good...

 

[Scott06]

Hello, so I bought a boat... its a pretty nice 1999 bayliner 1850ss with a 4.3L Vortec in it. Last owner owned it for about 13 years and always maintained it, always winterized it, etc... the boat runs great, the owner fired it up and it ran really well. Was holding very steady 600-700rpms on a cold engine. The owner said he hasn't used the boat much in the past few years. The boat was stored under an open shelter all the time with no covers on, at a lake house. Can condensation from temperature swings, weather and water get into the oil to make it look slightly milky? Its not creamy or milky(cappuccino) I checked the block no cracks nothing like that.... oil cap looks clean, also top inside of engine looks clean. Im honestly worried and hoping its just condensation in the oil... has anyone had this issue?

yes it can especially if the thermostat stays open. Take it out and get it good and hot for a long run. if it is cracked the oil level will rise, if not it should help cook it off. May need and oil change or two and burn it off by pushing the throttle forward