Calling all mechanics
 

I have a cigarette 38 foot top gun. Just bought it new to the powerboating game with twin engines been doing some trailer work on it testing the trailer out after my modifications and decided to run the boat a little bit on the water since I was out there anyway ran it for about 20 minutes at 40 mph roughly, they're turning 3200 RPMs stopped and checked the oil and I have water in one of the engines the oil was milky so I shut it down and brought it home, I've been asking questions doing some research just seeing what is on everyone's mind what this problem could be I instantly assumed Head gaskets and or intake gasket after researching I was told could possibly be exhaust manifolds. It has 565 dart blocks Merlin heads Merlin intakes on them haven't had much chance to run them since I just bought it a month ago and it got cold here so now I need to dig into it and see if I can find out what's wrong with it. Any input would be greatly appreciated, first on my list is to do a compression test
I wish i could post pictures but I don't think I'm allowed

Were your engines winterized prior to the freezing cold weather ?

what brand of exhaust does it have?

Yes they were winterized. And not sure. There a on piece manifold and riser. Wish I could post a pic but don't know how I probably don't have enough posts on the site to do that I'm assuming?

Host them at photobucket then copy and paste or become a paying member .

http://i147.photobucket.com/albums/r...31AA1CCF63.jpg

http://i147.photobucket.com/albums/r...0AE2EA882B.jpg

those look like old school kaama manifolds...the first thing i would do is contact the guy you bought it from and make him pay for it..you might have a bad intake gasket..also make sure the engine is getting to temperature..if its cold out it could be condensation but you would have it in both..

First thing I'd do is check plugs and find the wet hole or holes. Then check that manifold and do a leak down test if you find wet plugs. If everything checks out its probably an intake gasket

Ayuh,.... How were they winterized,..?? by Whom,..??

Those exhaust systems are Hardin p1000 's . They are probably OEM on that boat . I would definitely look at them first . I bet there almost 30 yrs old , way past there life expectancy, even in fresh water.. Tom

Sounds like a fancy set up ,if its running scuppers for water pick ups and you have a flush point ,and both motors seems to run same shut the water valve by scupper pull dump hose off exhausts and add 15psi see if it holds ..can pull dist and peek into valley with small mirror and look there too . Start easy and work your way in

And wow kamma manifolds huh ? Haven't seen any of those in eons

I winterized them bondo. 8 gallons of antifreeze per motor. Plus it sits inside a shed that doesn't drop below 40 So it had minimal time out in the elements. The trailer ride to the lake from the shop would be the only time out and it was 60degrees out so I'm pretty sure it's not poor winterization

Thanks for all the info guys this def helping. I was wondering what kind of manifolds those were my self

It could be as simple as condensation not burning off. Is there an increase in height on the oil level or just milky????

Do you have thermostats????? I could be just very cold lake water going through the crossovers and not building enough temp.

After I switched from a circulating system to crossover , I would occasionally see the oil turn a little milk - shake , running it hard for a few minutes took care of it ...this was an older Mercury HP465

Ayuh,.... Then freezin' seems to be 'bout the most remote of possibilities,....

Do as airjunky says,...

Drain the coolin' system, block it off/ isolate it, 'n plumb in a pressure gauge, 'n air fittin' to pressurize it,...
It oughta hold 15 psi pretty much Forever,....

If it don't,... follow the sound of the escapin' air,...

http://i147.photobucket.com/albums/r...3AF99DA85C.jpg

I drained a little bit of oil out of each engine to take them to get samples it's pretty obvious which is the one with the problem I think it's a little more than just condensation another person told me to check on condensation I wish that was the problem I don't think it is think it's a little more deeper than that

Yea that looks to be a little more than condensation . Good luck on the exploratory surgery and it is good to see that you keep a close eye on your machine . Welcome to OSO . There is a wealth of knowledge here .

if you find that you have a bad manifold their was a thread with some for sale a few weeks ago..

found it,,, http://www.offshoreonly.com/forums/s...ed-prices.html

+1

If it were the exhaust manifolds leaking that much water it would have hydro-locked, at the very least you would see excessive moisture on the plugs. I have a crossover setup with a thermostat and boat in 34 degree water and have never had my oil look milky, I'm betting on intake or head gaskets.

first thing i would do is remove the exhaust manifolds and pressure check them.real good chance this is the culprit.

Bad manifolds!

Yup,,,,,I agree,,,, pull the plugs and look for a wet/rusty one leading to exhaust manifold,,,,, if not Id be pulling the intake next

Can also have a leaking oil cooler. Just another thing to look into

sicktrickrick I'm local to you so let me know if you need anything. I was thinking along the lines of Griff at first but appears to be more than just condensation. Your boat might have been talked about to me a couple weeks ago at a local bar by the owner. She was asking me about size limits on Clinton Lake.