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Need help cruising home on one engine

J

jclays

Regular Contributor
Twin 350s raw water cooled. Never gets over 125 degrees. Cruising at 2400 rpm 10 miles out. Port engine drops 400 rpm smells hot. Open hatch left side viewed from above smoking between the head and manifold shut down. Hot metal sound and boiling water sound. Right side of engine pretty normal. Slow to restart idled to circulate water. Then shut it down to come home. That manifold and elbow new as of last year
 
Verrry hot on the left side (looking from the rear) of my port engine. Would a bad thermostat or oil cooler cause this issue? Can stay cool enough at idle speeds. Any faster gets hot.
 
IMO, if the hull is not yet up on step, 2,400 is a lousy rpm to sustain! At this rpm, the engine can become very detonation prone. All it takes is poor fuel quality, excessive ignition advance, excessive engine heat and a heavy workload…..... and you have a recipe for Marine load detonation.

Be careful!
 
1966 28’ Californian 2400rpm gets me crusing at 16 knots nicely on plane. This is the first time in 12 years I got hot. Why only one side?
 
As I suspected the thermostat was deteriorated and frozen badly. Removed the thermostat and replaced the plastic pressure relief valve. Reassembled without the thermostat just to see if that was the issue. Left side of the engine exhaust manifold too hot to keep your hand on it after half hour idle exhaust elbow just warm. Right side of engine the manifold was warm. You can keep your hand on it. Any ideas?
 
I would guess you have a blockage some where. Have you used anything other then your hand to get temps? How does your water flow compare from one engine to the other? Check your hoses, it could be you have one that is partialy collapsed.
 
missnancy said:
I would guess you have a blockage some where. Have you used anything other then your hand to get temps? How does your water flow compare from one engine to the other? Check your hoses, it could be you have one that is partialy collapsed.
Click to expand...

Water flow is comparable to the other side. Have not used a heat gun but it is hot enough to discolor the Crusader blue paint and not able to keep your hand on the manifold. Next week I will remove the manifold and elbow even though it is new and check it out. I had this problem last year and thought it was the manifold and elbow. I hadn't had time to try it out until Friday. Could it possibly be a blockage in the head?
 
Is the boat a closed system or raw water cooled? If it is raw water cooled there is a possibility but if its a closed or fresh water cooled you "should" be
ok. How many hours on the engine?
 
jclays said:
1..... 1966 28’ Californian 2400rpm gets me crusing at 16 knots nicely on plane.
2.... This is the first time in 12 years I got hot. Why only one side?
Click to expand...


1.... I am having difficulty believing that 2,400 rpm gets this 28' hull up on step. As said, this can become a detonation prone RPM.

2.... Many times the "spent" seawater is restricted on the side whereby the manifold/elbow runs hot.
The cure is to find out where the restriction is.
DO NOT restrict the opposite side in hopes of curing the issue with the hot side.

Start at the housing where the spent seawater is split and heads towards both exhaust systems.
Look closely at the area where the seawater is split or divided.
The portion that divides the seawater flow must divide it equally.

Pull the elbows and examine the seawater transfer ports. If they are rusty, clear them out.
Make certain that the transfer port gaskets are both the same. In other words, is one is fully open, the other one must also be fully open.

Look closely at the interior of any 90* fittings.
Do the same with the supply hoses.



jclays said:
............. Could it possibly be a blockage in the head?
Click to expand...

I would have to say NO!

Closed Cooling System: the E/G coolant is captive within a closed loop.
A full system closed loop will include the exhaust manifolds. A half system closed loop will include engine only (exhaust manifolds being raw water cooled).
The coolant sent to the exhaust elbow and out, will be seawater (i.e., river, lake or ocean water) and should be diverted equally.

Raw Water Cooling: the seawater (coolant) used for the cylinder block and cylinder heads becomes mixed with incoming seawater.
The mix occurs within the T-stat housing.
It is then to be diverted equally and sent on to the exhaust system.






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Good morning
The engines are 100% raw water cooled. I will disassemble the manifold and elbow again this weekend. The raw/cooling water gets split at the thermostat. I was excited to see the thermostat badly deteriorated and frozen. In clearing this I hoped that it would open up the water flow to that side of the engine. The only hoses I haven't cleared yet are the ones that come off the intake manifold and feed the exhaust manifold thru a fitting in the front of the manifold.
Thanks again guys. I will post my findings hopefully by Saturday afternoon.
Thanks
Jim
 
if the exhaust elbow isn't clogged, the next likely spot would be the tstat cover and the hoses from the cover to the exhaust manifolds.

also, a couple of connectors and two short lengths of clear hose (ID matching the hose feeding the water to the exhaust manifold) may be useful for inspecting the flow. many times, removing the hose to check the flow causes pressure differences in the system that aren't accurate indicators. another item that can help is a small pressure gauge that fits the drain plugs on the elbows....
 
....................
............. The raw/cooling water gets split at the thermostat.
Actually, the thermostat has nothing to do with splitting or diverted the seawater to the exhaust system.
Think of the thermostat as a temperature sensing valve. As is senses temperature, it begins to open and allows coolant (seawater in this case) to leave the cylinder block/heads as needed.

The only hoses I haven't cleared yet are the ones that come off the intake manifold and feed the exhaust manifold thru a fitting in the front of the manifold.
That would be the T-Stat Housing.
And yes.... look at the outlet ports on the T-Stat Housing, and look at the inlet fittings on the manifolds.
Click to expand...



makomark said:
if the exhaust elbow isn't clogged, the next likely spot would be the tstat cover and the hoses from the cover to the exhaust manifolds.
Yes, the T-stat housing is where the seawater is split/diverted. I have seen rust scale on one side cause an uneven flow.

also, a couple of connectors and two short lengths of clear hose (ID matching the hose feeding the water to the exhaust manifold) may be useful for inspecting the flow. many times, removing the hose to check the flow causes pressure differences in the system that aren't accurate indicators.
another item that can help is a small pressure gauge that fits the drain plugs on the elbows....
Great idea. There can be a correlation between pressure and flow.
Click to expand...


Hang in there Jim....... you will find the problem! :D




Twin 350s raw water cooled. Never gets over 125 degrees.
125*F is too cool for these engines.
If you are running in river/lake water, you can use 160* stats. If in ocean water, you will want to use the 145* stats as to minimize salt crystallization.
Click to expand...



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Good Morning
The only hoses I haven't cleared yet are the ones that come off the intake manifold and feed the exhaust manifold thru a fitting in the front of the manifold.
That would be the T-Stat Housing.
And yes.... look at the outlet ports on the T-Stat Housing, and look at the inlet fittings on the manifolds.

My intake manifold is the old 1966 Crusader/Chevy intake that has 2 fittings on the intake manifold itself a few inches away from the thermostat housing. one for each side that feeds into or out of the exhaust manifold. I will pull these hoses Saturday and the exhaust elbow as well to check if it is clear. Should I pull these hoses one at a time with the engine running? I do not know what to expect as far as water flow.

Can we post pictures on this forum?
 
Yes on pics - see this: http://www.marineengine.com/boat-forum/faq.php?faq=vb3_reading_posting#faq_vb3_attachments


A pic of the intake plumbing around the tstat would be helpful - that stuff is almost my age...

You can pull them running but expect to get wet.....I'd be incline to remove them w/ the engine off and check for obstructions in the fittings....or the hose itself - sometimes the inner layer delaminates and you get a flap that becomes a restriction...
 
Engine.jpgThis is the starboard engine. The port side is apart. This will show the hose configuration. I will send another reply with another picture. Its not letting me add a second picture. Unable to add a second picture. The thermostat housing is 2 pieces. One hose from the raw water pump enters in the low half below the thermostat. Also from the lower housing a second hose goes to the circulating water pump on the engine block. The two hoses on the upper thermostat housing go to the elbows. There is a pressure relief valve in the front of the top half between the 2 hoses. There are 2 hoses that exit the intake manifold from a fitting on the intake manifold each goes to the front of the exhaust manifold.
 
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Engine1.jpgHeyhey Second picture up loaded. Closer view of the thermostat housing.
Replaced one hose from INTAKE manifold to the front of the exhaust manifold with clear plastic hose. Good water flow there. Also replaced one of the upper hoses from the thermostat housing to the T fitting on the exhaust elbow. Some flow here but not much. This is one of the hoses that are between the pressure relief valve on the upper thermostat housing. I did not reinstall a thermostat when I found the corroded one just for testing the flow and heating issue. I wonder if installing the the thermostat will improve the flow in the upper hoses. Im thinking the pressure relief valve needs the thermostat to work properly.

Ive removed the raw water pump and checked the impeller and everything is good. Removed the engine circulating water pump a little corrosion here but still working fine and not blocked. I have a new one in my locker and will install the new one. Ill replace the gaskets in the old one and save it for an emergency spare.

Tomorrow I'll reinstall the pumps and hoses with a thermostat and see how it all works. Not sure where else the problem may be.
Possibly a blown head gasket?
 
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that seems like a lot of extra plumbing.....but its a 50+ year old design......are there any additional hoses connected to the exhaust manifold?

Also, when the new elbows when on, which gasket style was used?

Yes, the poppet valve in the tstat housing needs the tstat correctly installed for it to function properly.

On the original pic, there's a few wire nuts - they should be replaced with heat shrink crimp on connections for reliability....
 
Only 2 hoses to the manifold. One feeds into the front of the exhaust manifold the second to the fitting on the elbow. The elbow gasket was the one with one opening positioned at 12 oclock
 
Ok...so ONE hose feeds each exhaust manifold and one hose feeds each elbow....and the combination dumps into the exhaust.....

The hoses from the intake going to the exhaust manifolds in essence bypass the poppet valve - that's likely why you never get up to the t-stat temp.

Also, with the plumbing like that, if the exhaust manifold-elbow connection gets clogged/restricted, the water won't exit the manifold and it will get hot....
 
makomark said:
Ok...so ONE hose feeds each exhaust manifold and one hose feeds each elbow....and the combination dumps into the exhaust.....

The hoses from the intake going to the exhaust manifolds in essence bypass the poppet valve - that's likely why you never get up to the t-stat temp.

Also, with the plumbing like that, if the exhaust manifold-elbow connection gets clogged/restricted, the water won't exit the manifold and it will get hot....
Click to expand...
How should. It be plumbed? That’s the way she was when I bought her used
 
Reassembled port engine. New therstat , poppet valve and new circulating water pump. Idled both engines. After 30 mins at 700 rpm port engine exhaust manifold 140 to 170 degrees in various places. The center being the hottest. That was the left side of the engine. The right side about 10 degrees cooler. Viewed from behind. Increasing the rpm to 1500rpm cooled the exhaust manifolds to 106/108 degrees. Matching the starboard engine. Temps taken with infrared gun.
 
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jclays said:
How should. It be plumbed? That’s the way she was when I bought her used
Click to expand...

Like opinions, there are multiple ways to plumb up cooling systems....being as you have it running, you may not want to change anything. Being as it runs well below the t-stat's temp, it may be worthy of consideration to increase whatever time you have remaining on the engines.

I'd be inclined to remove the hoses from the intake manifold and plug the holes.....same for the connections at the exhaust elbows.... Since you have the appropriate gaskets, I would route the hoses from the t-stat housing to the exhaust manifolds. This will keep the block on the high pressure side of the t-stat.....
 
makomark said:
Like opinions, there are multiple ways to plumb up cooling systems....being as you have it running, you may not want to change anything. Being as it runs well below the t-stat's temp, it may be worthy of consideration to increase whatever time you have remaining on the engines.

I'd be inclined to remove the hoses from the intake manifold and plug the holes.....same for the connections at the exhaust elbows.... Since you have the appropriate gaskets, I would route the hoses from the t-stat housing to the exhaust manifolds. This will keep the block on the high pressure side of the t-stat.....
Click to expand...

I was thinking of trying this after googling some older crusader pictures on line..Now on a side note. The Tstat housing has a block off plate underneath it. There is no hole in the intake manifold below the tstat housing. It is just bolted on to the intake manifold. The water into the engine comes via the raw water pump to tstat housing and tstat housing to circulating water pump on the engine block. I believe this to be ok since the fittings on the intake manifold feed the exhaust manifold.

Did you see post #23? Your Thoughts?
Thanks
Jim
 
jclays said:
.....The Tstat housing has a block off plate underneath it. There is no hole in the intake manifold below the tstat housing......
Click to expand...

So what you are saying is the thermostat aint in the cooling flow at all......and neither is the poppet valve - that will keep the engine from getting up to temp and cause hot spots.......

anything else "uncommon" regarding these engine configurations???

Regarding Post #23....yes, that's what the "..because you have it running..." caveat was added in post 24. Its your call whether to leave it as is or try to optimize what you have.....based on what you have shared, the tstat and the poppet valve are just ballast and cant do what they were intended to do....
 
makomark said:
So what you are saying is the thermostat aint in the cooling flow at all......and neither is the poppet valve - that will keep the engine from getting up to temp and cause hot spots.......

anything else "uncommon" regarding these engine configurations???

Regarding Post #23....yes, that's what the "..because you have it running..." caveat was added in post 24. Its your call whether to leave it as is or try to optimize what you have.....based on what you have shared, the tstat and the poppet valve are just ballast and cant do what they were intended to do....
Click to expand...

Wouldnt the hose from the raw water pump into the thermostat housing and the hose to the circulating pump take the place of the the opening in the intake manifold?
 
jclays said:
Wouldnt the hose from the raw waterpump into the thermostat housing and the hose to the circulating pump take theplace of the the opening in the intake manifold?
Click to expand...
no, I don't believe so.....the hose from the raw waterpump to the tstat housing is how the cooling water is introduced into the tstathousing chamber and should remain. the hose from the tstat housing to thecirculating pump is the path for the cooling water to get into the engine.Normally, from the circulating pump, the water will flow thru the block andexit thru the tstat, once it opens. The tstat restricts the flow of waterexiting the block until it has warmed enough to open up....then it get sent tothe exhaust. With the hoses from the intake manifold to the exhaust manifold,the water in the block flows directly into the exhaust manifolds with norestriction, ie the t-stat is bypassed.

 
makomark said:
no, I don't believe so.....the hose from the raw waterpump to the tstat housing is how the cooling water is introduced into the tstathousing chamber and should remain. the hose from the tstat housing to thecirculating pump is the path for the cooling water to get into the engine.Normally, from the circulating pump, the water will flow thru the block andexit thru the tstat, once it opens. The tstat restricts the flow of waterexiting the block until it has warmed enough to open up....then it get sent tothe exhaust. With the hoses from the intake manifold to the exhaust manifold,the water in the block flows directly into the exhaust manifolds with norestriction, ie the t-stat is bypassed.
Click to expand...
Found a vintage Christ Craft boat shop in L.A. Harbor that also deals with vintage Crusaders. There is an old Crusader parts diagram that shows a very different lower thermostat housing. Picture the current tstat housing I show in my pictures but with a hollow bridge on each side that bolts to the intake manifold where the fittings are that have a hose to my exhaust manifolds. Instead of feeding the exhaust manifolds from the intake manifold they feed the the tstat housing under the tstat. The manifolds are fed from the hoses that my pictures depict 1 1/4 inch hoses from each side of the tstat to the exhaust elbows. those go to the front of the exhaust manifold. nothing to the elbows. Simple.

This "Low Profile Lower Thermostat housing" is no longer available thru Crusader or anyone else. I did find a Riva boat shop in Italy yes Italy that show it on their parts catalog they are out but in turn directed me to a guy in Florida that had a couple of used ones. He will probably want a mint for them. I am thinking about talking to a local machine shop and having them modify the existing lower tstat housing with 2ea 1-1/4 inch pipe nipple and running a hose from the hose fittings on each side on the intake manifold to feed the lower tstat housing. In essence duplicating what the original part was doing.
thanks in advance
Jim

[/QUOTE]
 
makomark said:
that seems like a lot of extra plumbing.....

I agree.
Click to expand...

jclays said:
How should it be plumbed? That’s the way she was when I bought her used.
Click to expand...


jclays, the raw water cooled engine plumbing has undergone many changes since the old days. It is actually more efficient now days.
If this was my boat, I would rid myself of that old and odd style plumbing and I would re-configure it into a more modern style.
You would have fewer issues (if any) and it would simplify things for you.
Regarding your post # 29..... No expensive OEM parts...... no hunting for NLA parts....... no machine shop modifications....... and so on!

Do it once, and don't look back! :D


Just a thought!



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