Engine plumbing question 76 250 with 350

[leonardo]

I have some questions about how the hoses should be run.  Does anyone know of a layout or photos of the typical plumbing for a 76' 240 with the 350 engine.  Some of my hoses were cut in order to completely drain the system by the previous owner.  I also have to 3/4" hoses removed from the tops of the exhaust near the front of the engine that I'm not sure of why they are there.  My email address is leonmlr@yahoo.com and phone number is 240-876-9194.  Thanks.

[GoneFission]

Do you know which version of engine you have?  Crusader?  The best money you can spend is to get a service manual for the engine.  That being said, the 3/4" hoses on the top of the exhaust risers are water feeds to cool the exhaust.  

Is your boat a full inboard or an inboard/outboard?  The hoses are different.  A full inboard will have the normal engine driven water pump on the front of the engine, then a separate belt driven water pump alongside one head.  The I/O uses the water pump in the lower unit and the engine driven water pump.  Since the water flow is different depending on inboard or I/O, we need to know which version you have to help with hoses.

[leonardo]

full inboard.  Where could I get a manual or at least a plumbing diagram?

[leonardo]

I should add it looks like I have two heat exchangers.  One on each side of the compartment witha cross over hose from one to the other.  Is the cross over coolant or raw water?

[wingtime]

Does your exhaust have the risers in the middle of the manifold or the rear of the manifold?  On my 79 Slickcraft the risers were on the rear and there were block off plates with barbs for 3/4" hoses on the front of each manifold.  I don't recall but it may have cooling hoses on the back too. I did not have a exchangers so I'm sure it was plumed different.

[leonardo]

On each exhaust manifold I have a 3/4" hose attaching to the front and it runs to the rear of the manifold where it connects to the exhaust pipe.

[RickK]

Pictures would sure make this easier.  

[GoneFission]

Leo - what you have is a Fresh Water Cooled (FWC) engine.  This is the best system for boats that run in salt water, because the salt water never contacts the inside of the engine.  You have 2 cooling loops:

The primary loop is closed and cools the engine.  You should  have a small reservoir on top of the engine with a cap like a radiator cap.  The primary loop has a 50-50 water anti-freeze mixture in it, so you don't have to winterize that part of the engine.  All that's required for primary loop maintenance is keeping the system full and checking for leaks.  

The secondary loop brings in raw water (seawater) from an thru-hull, runs it through a strainer, pumps it into the heat exchangers to cool the primary coolant, and then it goes into the exhaust risers to cool the exhaust gases.  The secondary loop uses an engine driven pump (usually run by a belt off the crankshaft) to pump water.  

I still don't know what make of engine you have, but here's a typical flow path that should help you:
 

See ya on the water!

[leonardo]

Great!  That diagram is very close.  The exchange tanks I have are one on each side of the engine room with a crossover pipe.  I blew compressed air into the raw water end and it went out at the cross over so it looks like they connect via that pipe.  The engine does have 50/50 mix and the small expansion tank is mounted at the top front of the engine (350).  I just lubed the cylinders with upper cylinder lube and turned over the engine by had with out the sparkplugs.  I want to start the engine and plan to connect the raw water inlet to a garden hose to supply water to the raw water pump and exchangers.  right now All I lack is a carburator and have been bidding on one on ebay.  I have the old carb and someone was going to rebuild for the previous owner but that never happened and some parts were lost.  I'm pulling the cover for the fuel tanks this afternoon to clean and inspect.  The previous owner said he thought it would not need much to get in the water and so far he was right.  I need the boat to go from Crisfield, MD to Tylerton, MD about 12 miles open water in the Chesapeake Bay.  I have a holiday home on Smith Island and want to ferry my own repair materials to the island plus not be bound by the twice a day ferry schedule, 12:30 pm and 4 pm.  Not very helpful for my use.  I have to admit this has been one of the most helpful internet connection/groups I have ever been involved.

[GoneFission]

Glad to know it helped.  The good news is that raw water cooled engines usually have a life of about 1000 hours in salt water, whereas fresh water cooled engines usually last about 2000 hours.  Once you get it sorted out, you should expect your engine to be good for a while.  You still have not indicated the engine manufacturer, but here are some links that may help:

Crusader:
http://www.marinepartssource.com/crusad ... 07dp63.asp  

Mercruiser:
http://www.perfprotech.com/store/assemb ... 61-31.aspx  

You should be able to find a carb on eBay - lots of these engines around.  Good luck!

[leonardo]

Carb is installed and I'm getting ready to start.  The plumbing has been resolved. One heat exchanger is for coolant and the other is for cooling the oil.  It's hooked up to the transmission with two hydraulic lines.  The cross over takes the raw water from the coolant side to the oil side of the exchangers.  I only need to replace one more hose (the cross over) and two fittings from the front of the exhaust risers, they are very rusty and I would feel better with them replaced.  I've oiled the cylinders and turned over the motor a number of times, oil pressure comes right up to 40+psi and compressions seem good so tomorrow I'll reinstall the sparkplugs add gas and see if it starts.

[GoneFission]

Good job Leo!  I see a nice spash in your future!  

Post some pics of her running when you get her on the water.