Cracked head, water in the oil

dippasan · 07-17-2023, 08:41 AM

Good morning all.
Looking for some advice. We own a 23' larson bow rider with an MC 5.7 and Bravo 3 for our son's to use with their families when they come up. Great little boat. (No way they're using my boat).

My story:
I had that "holy $4it" moment during spring start up and discovered that wonderful milky colored oil in the crank case. I know it could be head gaskets or worse. I decided to dig into it last week. I removed the entire top end off the motor. Took the heads to a machine shop where magnafluxing revealed a cracked head. Head gaskets were junk also. The machine shop has a set of heads that have had a complete valve job ready to be bolted on. I think the lower end of the motor is ok but hard to tell. for that reason I'm willing to dump the $600 for the heads in hopes the lower end is ok. The boat is worth maybe $10k so it's hard for me to justify a $5-7k long block replacement. I'm trying to affect repair with minimal cost.

Do any of you have experience with a similar situation?
What's the best way to remove the water/oil from the crank case? Kerosene? Marvel mystery oil? Multiple oil changes? I'll try to get as much out as I can with my hand pump but it's pretty thick stuff.

Thanks in advance for your replies.

WinnisquamZ · 07-17-2023, 08:59 AM

Sounds like a plan. New heads, gaskets and top end. Drain. Use sea form. Fill her up and go. If not, one of the donor companies will take it. Plenty of good used boats available

Sent from my iPhone using Winnipesaukee Forum mobile app

fatlazyless · 07-17-2023, 10:28 AM

Before you do anything else, suggest you take a look at all the different JB Weld marine epoxy repair items for about ten dollars sold on Ebay and what's been fixed with it.

JB Weld-marine for the cheap fix!

dippasan · 07-17-2023, 11:22 AM

Quote:

Originally Posted by fatlazyless

Before you do anything else, suggest you take a look at all the different JB Weld marine epoxy repair items for about ten dollars sold on Ebay and what's been fixed with it.

JB Weld-marine for the cheap fix!

Hmmmmm, I've used JB Weld for a lot of things, but for a cracked head in a boat, I don't think so, especially when my grandkids will be riding in the boat

Poor Richard · 07-17-2023, 12:39 PM

The steps I suggest:

Dump existing oil milkshake from engine

Fill with fresh oil, crank the engine over for a few seconds but do not start it.

Repeat that process until the obvious water contamination has been removed.

When I say "obvious" I mean "the oil looks milky". You want to eliminate that first before firing the engine up.

Once the oil comes out clear-ish looking, fill with oil and run it up to operating temp.

Shut the engine off and let it sit for at least 5min.

Check oil level and visual quality of oil.

Edit: if you're worried about damage to the engine, consider an oil analysis from a lab such as Blackstone

Descant · 07-17-2023, 02:24 PM

I used to go to M & M in Meredith for used parts and once, an engine. I think they closed awhile ago. What happened to their inventor? Anybody else in that business?

dippasan · 07-17-2023, 02:38 PM

Quote:

Originally Posted by Poor Richard

The steps I suggest:

Dump existing oil milkshake from engine

Fill with fresh oil, crank the engine over for a few seconds but do not start it.

Repeat that process until the obvious water contamination has been removed.

When I say "obvious" I mean "the oil looks milky". You want to eliminate that first before firing the engine up.

Once the oil comes out clear-ish looking, fill with oil and run it up to operating temp.

Shut the engine off and let it sit for at least 5min.

Check oil level and visual quality of oil.

Edit: if you're worried about damage to the engine, consider an oil analysis from a lab such as Blackstone

So I was able to get all the milky oil out with my hand pump. I put in a quart of automatic tranny fluid before I started pumping to try and thin it out. Seemed to help. I'll try one more qt of tranny fluid after I reassemble the engine to try to get some more contaminated oil out.
I like your recommendation of cranking with fresh oil but not starting then doing another oil change. I hope to have it reassembled by beginning of next week.

Thanks for the tips!

07-17-2023, 08:41 AM	#1
dippasan Senior Member Join Date: Sep 2011 Location: Hooksett NH and Sleepers Isl Posts: 392 Thanks: 287 Thanked 190 Times in 83 Posts	Cracked head, water in the oil Good morning all. Looking for some advice. We own a 23' larson bow rider with an MC 5.7 and Bravo 3 for our son's to use with their families when they come up. Great little boat. (No way they're using my boat). My story: I had that "holy $4it" moment during spring start up and discovered that wonderful milky colored oil in the crank case. I know it could be head gaskets or worse. I decided to dig into it last week. I removed the entire top end off the motor. Took the heads to a machine shop where magnafluxing revealed a cracked head. Head gaskets were junk also. The machine shop has a set of heads that have had a complete valve job ready to be bolted on. I think the lower end of the motor is ok but hard to tell. for that reason I'm willing to dump the $600 for the heads in hopes the lower end is ok. The boat is worth maybe $10k so it's hard for me to justify a $5-7k long block replacement. I'm trying to affect repair with minimal cost. Do any of you have experience with a similar situation? What's the best way to remove the water/oil from the crank case? Kerosene? Marvel mystery oil? Multiple oil changes? I'll try to get as much out as I can with my hand pump but it's pretty thick stuff. Thanks in advance for your replies. __________________ Luck is when preparedness meets opportunity

07-17-2023, 10:28 AM	#3
fatlazyless Senior Member Join Date: Apr 2004 Posts: 8,740 Blog Entries: 1 Thanks: 300 Thanked 1,007 Times in 735 Posts	Before you do anything else, suggest you take a look at all the different JB Weld marine epoxy repair items for about ten dollars sold on Ebay and what's been fixed with it. JB Weld-marine for the cheap fix! __________________ ... down and out, liv'n that Walmart side of the lake!

07-17-2023, 02:24 PM	#6
Descant Senior Member Join Date: Mar 2006 Location: Merrimack and Welch Island Posts: 4,350 Thanks: 1,341 Thanked 1,622 Times in 1,054 Posts	M & m I used to go to M & M in Meredith for used parts and once, an engine. I think they closed awhile ago. What happened to their inventor? Anybody else in that business?

07-17-2023, 08:59 AM	#2
WinnisquamZ Senior Member Join Date: Dec 2016 Posts: 2,050 Thanks: 210 Thanked 652 Times in 435 Posts	Sounds like a plan. New heads, gaskets and top end. Drain. Use sea form. Fill her up and go. If not, one of the donor companies will take it. Plenty of good used boats available Sent from my iPhone using Winnipesaukee Forum mobile app

The Following User Says Thank You to WinnisquamZ For This Useful Post:
dippasan (07-17-2023)

07-17-2023, 12:39 PM	#5
Poor Richard Senior Member Join Date: Aug 2017 Location: The humbling river Posts: 304 Thanks: 42 Thanked 80 Times in 57 Posts	The steps I suggest: Dump existing oil milkshake from engine Fill with fresh oil, crank the engine over for a few seconds but do not start it. Repeat that process until the obvious water contamination has been removed. When I say "obvious" I mean "the oil looks milky". You want to eliminate that first before firing the engine up. Once the oil comes out clear-ish looking, fill with oil and run it up to operating temp. Shut the engine off and let it sit for at least 5min. Check oil level and visual quality of oil. Edit: if you're worried about damage to the engine, consider an oil analysis from a lab such as Blackstone

The Following User Says Thank You to Poor Richard For This Useful Post:
dippasan (07-17-2023)