SailNet Community banner

1 - 20 of 28 Posts

·
Registered
Joined
·
292 Posts
Discussion Starter #1 (Edited)
Putting some feelers out there to figure out what’s going on with my engine.

Boat is a 1970 Tartan 34C with a Yanmar 3GM30F engine. Vetus waterlift muffler.

Occasionally gets water in the number one cylinder (furthest aft). This has happened six times in the last 7500 NM’s.

Does not matter if the boat was on a port or starboard tack nor does it matter how long I’ve been on that tack. I’ve went days on one tack or the other in various conditions with no issues. It’s never happened after motoring in calm conditions though so it’s definitely linked to heeling in either direction.

Does not matter if I close the raw water seacock or leave it open.

The exhaust outlet is at the waterline on the port side. Exhaust hose runs up to the gunwhale then down to the Vetus muffler which is roughly at the waterline. The exhaust hose bend is about 3’ above the waterline.

The small hose for the manifold runs up in the original “post” that once held the factory lift muffler for the Atomic 4. It is above the gunwhale and has a Marlon anti-siphon valve installed. I’ve replaced the anti-siphon valve and cleaned the manifold riser that connects to both the large and small hose. There is no carbon build up.

First pic shows the exhaust outlet. Second show me pointing to where the anti-siphon valve is located, third shows the waterlift muffler location and the last shows the system assembled.

Before completely redoing the exhaust system with a waterlift muffler that attaches directly to the exhaust outlet on the hull Id like to see if I’m missing something.

I am very familiar with how this system works but I’m stumped here.

See attached pictures for the current setup. Any ideas?
 

Attachments

·
Master Mariner
Joined
·
8,235 Posts
The vented loop on the seawater line running to the mixing elbow isn't functioning correctly. Only other thing I can think of is a blown head gasket.

We had that happen and tore the engine down half a dozen times, cut the monel elbow in half looking for a hole, and a bunch of other stuff, all the while rubbing the vented loop's hose with my elbow. Didn't even think about it. Cleaned it up (bronze, not plastic) and haven't had a problem since.
 

·
Registered
Joined
·
292 Posts
Discussion Starter #4
1st thought is clogged exhaust elbow
That’s what I had originally thought as well. I removed the elbow, acid cleaned it and reinstalled with new gaskets. It wasn’t clogged in any way when I did that. Things were fine from Savannah Georgia to Houston Texas and then it happened again last week after a short afternoon sail in 10-15 knots= never heeled more than 15° and certainly didn’t put the rail in the water even once. I was on a port tack for an hour and then a broad reach for two hours, then a starboard tack for about thirty minutes. Went to start the engine and it happened again. Closed the seacock, released all compression levers and blew the engine out, reversed the procedure and it started. .........
 

·
Registered
Joined
·
292 Posts
Discussion Starter #5
The vented loop on the seawater line running to the mixing elbow isn't functioning correctly. Only other thing I can think of is a blown head gasket.

We had that happen and tore the engine down half a dozen times, cut the monel elbow in half looking for a hole, and a bunch of other stuff, all the while rubbing the vented loop's hose with my elbow. Didn't even think about it. Cleaned it up (bronze, not plastic) and haven't had a problem since.
The original anti-siphon Loop was removed and the valve cleaned. It did have a residue in it. I have since installed a new loop, about 3000 nm’s ago. Thought I had fixed it until it happened again. While possible I don’t see how it could have failed again so quickly. I’ll take the new one apart and check though.

Want to add that this boat doesn’t sit much as I’m a full time cruiser/live aboard. The engine rarely idles for long and when I do run it, it runs at cruising RPM (2900) for a minimum of an hour before reducing to idle, revving three times and shutting down in gear to activate my MaxProp.
 

·
Master Mariner
Joined
·
8,235 Posts
Want to add that this boat doesn’t sit much as I’m a full time cruiser/live aboard. .
At the time that happened, we didn't sit much either, but we did a whole lot more sailing than powering, so the engine sat idle a lot. One season we did 2k+ miles inter-island, w/only 20 hours under power.
We did 10 cruises between St.T. and Trinidad over a two season period, preparing to open our charter business.
 

·
Registered
Joined
·
2,826 Posts
when was the repower done and how long has the system run properly before this problem. it is a very short coupled system in that boat. all the components are close to the waterline. the exhaust outlet loop may be to high and holding a lot of water at shut down which then flows backward. you may need a anti siphon valve on the uphill side of the outlet loop lesson the amount of water flowing back to the engine. smaller exhaust line size bigger is not always better. try raving the engine just before shutdown to push out more water.
 

·
Registered
Joined
·
2,382 Posts
Putting some feelers out there to figure out what’s going on with my engine.

Boat is a 1970 Tartan 34C with a Yanmar 3GM30F engine. Vetus waterlift muffler.

Occasionally gets water in the number four cylinder (furthest aft). This has happened six times in the last 7500 NM’s.
I can’t figure out where the fourth cylinder is on my 3GM30F. :wink
 

·
Senior Member
Joined
·
11,803 Posts

·
Registered
Joined
·
667 Posts
I had water get into the aft most cylinder (the No. 1 cylinder, the one nearest the flywheel) on my similar Yanmar 3HM35F. I did four things to stop that from happening. First, I added an extension pipe and coupling below the 'U' shaped exhaust elbow to raise it to the top of the engine compartment. Second, I removed the duckbill valve from the seawater siphon break replacing it with a short length of tubing that itself slips into a larger clear PVC hose that discharges into the bilge. Now, when the engine is running a small stream of water flows to the bilge, I can see it, and I know that the vent is not plugged. Third, I rearranged the exhaust hose running from the Vetus waterlock muffler to the exhaust outlet so that it rises as high as possible before dropping down to the outlet. And fourth, I replaced the old ball valve at the exhaust outlet with a new one that is much easier to turn, and I keep it closed when we leave the boat and when sailing downwind in lively conditions. Which was the fix? I don't know.

I also pulled the exhaust elbow from the engine and with a garden hose assured myself that the raw water came only out of the exhaust elbow's exit.

Bill
 

·
Registered
Joined
·
292 Posts
Discussion Starter #11
when was the repower done and how long has the system run properly before this problem. it is a very short coupled system in that boat. all the components are close to the waterline. the exhaust outlet loop may be to high and holding a lot of water at shut down which then flows backward. you may need a anti siphon valve on the uphill side of the outlet loop lesson the amount of water flowing back to the engine. smaller exhaust line size bigger is not always better. try raving the engine just before shutdown to push out more water.
It was done a couple years before I bought the boat. It happened a couple times when I first bought it (early 19’) and occasionally during the trip south. Happened last week. I hadn’t considered that the exhaust hose itself could be holding the water- then flowing into the engine. Hmmm.
 

·
Registered
Joined
·
292 Posts
Discussion Starter #12
Putting some feelers out there to figure out what’s going on with my engine.

Boat is a 1970 Tartan 34C with a Yanmar 3GM30F engine. Vetus waterlift muffler.

Occasionally gets water in the number four cylinder (furthest aft). This has happened six times in the last 7500 NM’s.
I can’t figure out where the fourth cylinder is on my 3GM30F. /forums/images/SailNet_Toucan/smilies/tango_face_wink.png
Hahahahha! Lol. You’re RIGHT! The problem is obvious now lol. I had been working on a 4 cyl all day and I guess that got stuck in my mind.
 

·
Registered
Joined
·
292 Posts
Discussion Starter #13
I had water get into the aft most cylinder (the No. 1 cylinder, the one nearest the flywheel) on my similar Yanmar 3HM35F. I did four things to stop that from happening. First, I added an extension pipe and coupling below the 'U' shaped exhaust elbow to raise it to the top of the engine compartment. Second, I removed the duckbill valve from the seawater siphon break replacing it with a short length of tubing that itself slips into a larger clear PVC hose that discharges into the bilge. Now, when the engine is running a small stream of water flows to the bilge, I can see it, and I know that the vent is not plugged. Third, I rearranged the exhaust hose running from the Vetus waterlock muffler to the exhaust outlet so that it rises as high as possible before dropping down to the outlet. And fourth, I replaced the old ball valve at the exhaust outlet with a new one that is much easier to turn, and I keep it closed when we leave the boat and when sailing downwind in lively conditions. Which was the fix? I don't know.

I also pulled the exhaust elbow from the engine and with a garden hose assured myself that the raw water came only out of the exhaust elbow's exit.

Bill
Interesting. Yeah I’m thinking I’ll have to completely rebuild the system and like you, basically build it from the manifold to outlet with back flooding in mind. The original Atomic 4 had the exhaust go straight up in the post (pic that I’m pointing at) and then down and out.

So you have a ball valve on the exhaust hose itself? No issues with it clogging or getting so full of carbon it won’t close?
 

·
Registered
Joined
·
667 Posts
So you have a ball valve on the exhaust hose itself? No issues with it clogging or getting so full of carbon it won’t close?
The original (1988) 1-1/2" ball exhaust outlet valve was a bit hard to turn partly because of its location and partly because of the valve itself. Before I replaced the valve I had a rubber stopper that would fit in the exhaust outlet. I'd plug the outlet with it. There was a stainless eye screw in the stopper with a cord that ran to the cockpit. That system worked too. The new (now maybe four years old) valve is still hard to reach, but it turns with little effort. I replaced the valve when the bronze elbow following it failed. It developed a hole in the outside of its turn.

Starting the engine with the stopper in place would blow the stopper out. Starting the engine with the valve closed stops the engine.
 

·
Registered
Joined
·
1,016 Posts
I don't trust anti-syphon valves. The one on my Westsail with Volvo MD2 would stick closed and the engine would flood. Solved it by replacing the valve on top of the Anti-syphon U with a 1/4 hose bib, attached a 1/4" hose to it and attached it to a 1/4" through hull high up on the top side with a loop as high as I could get it. Never had another problem with water back syphoning into the engine. Very occasionally would get a dribble of water out the through hull with the emphasis on very.
 

·
Registered
Joined
·
4,601 Posts
Wasps can build their nest in the pisser tube so 'almost' maintenance free. .Installing a ball valve in the bottom of the water muffler ??
 

·
Registered
Joined
·
80 Posts
I don't trust anti-syphon valves. The one on my Westsail with Volvo MD2 would stick closed and the engine would flood. Solved it by replacing the valve on top of the Anti-syphon U with a 1/4 hose bib, attached a 1/4" hose to it and attached it to a 1/4" through hull high up on the top side with a loop as high as I could get it. Never had another problem with water back syphoning into the engine. Very occasionally would get a dribble of water out the through hull with the emphasis on very.
Similar to mine except on mine the 1/4 inch hose is plumbed into a cockpit drain which is easy to see and no added through hull fitting. The hose run is way shorter as well. :)
 

·
Registered
Joined
·
76 Posts
Alanr77. I am not surprised that you get a hydrolock in your engine. The waterlift muffler is installed above the exhaust outlet on the engine. I suggest that you read the installation instructions for your Vetus muffler and also the Vernalift mufflers and for the Beta Marine exhaust design page on their website.

You have a few choices. One is to fit a taller riser to the engine and live with a tower on the engine box or you will have to change the exhaust system completely. The original exhaust on that boat was a standpipe which worked well.
 

·
Registered
Joined
·
292 Posts
Discussion Starter #19
Alanr77. I am not surprised that you get a hydrolock in your engine. The waterlift muffler is installed above the exhaust outlet on the engine. I suggest that you read the installation instructions for your Vetus muffler and also the Vernalift mufflers and for the Beta Marine exhaust design page on their website.

You have a few choices. One is to fit a taller riser to the engine and live with a tower on the engine box or you will have to change the exhaust system completely. The original exhaust on that boat was a standpipe which worked well.
It’s actually a couple inches lower static but on a port tack is definitely higher. Hadn’t thought about that before so you’re on to something. I didn’t do the install (previous owner) but it’s looking like a total rethink of the entire system. Thanks for that insight on it being lower. The original standpipe from what I’ve seen on A4 boats was much higher than the engine on all tacks.
 

·
Registered
Joined
·
292 Posts
Discussion Starter #20 (Edited)
Alanr77. I am not surprised that you get a hydrolock in your engine. The waterlift muffler is installed above the exhaust outlet on the engine. I suggest that you read the installation instructions for your Vetus muffler and also the Vernalift mufflers and for the Beta Marine exhaust design page on their website.

You have a few choices. One is to fit a taller riser to the engine and live with a tower on the engine box or you will have to change the exhaust system completely. The original exhaust on that boat was a standpipe which worked well.
Ok, here’s where I’m at. What appears to be happening is not a back flow or siphon occurring in the exhaust system. When on a port tack whatever water is in the large exhaust hose connecting the riser to the waterlift (or/and some water stored in the waterlift itself) is draining into the exhaust manifold as the hose and muffler rise above the riser on that particular tack. This explains why it seems to be linked to +15° of heel on a port tack and only happens intermittently.

Two solutions come to mind here.

1) Moyer Marine sells a replacement standpipe designed for this boat (Tartan 34C) that mimics the original. Issues here are that it’s designed for the Atomic 4 so the inlet and outlet are smaller than what I have. 1 1/4 on the Moyer unit. The A4 and my 3GM30 are very close in displacement (58-62) but due to the higher compression of the diesel, I’m not sure if this would be an issue or not regarding exhaust flow.

2) Install a bronze ball valve in the middle of the 2” exhaust hose between the riser and waterlift muffler. By closing this after engine shutdown it would prevent any water from flowing into the manifold. Once I either tacked or leveled the boat, any water caught between the valve and muffler would drain back into the waterlift and therefore not cause an issue.

Part of my SOP is to close the 3/4 seacock for the raw water system and clip the ignition keys to the seacock once underway. This prevents me from starting the engine with the seacock closed and the addition of the 2” valve would simply add another step to this.

Any opinions on which method would be preferable? I kind of like the ball valve idea as it seals the only “open” to the outside of the hull I have left, as all my automatic bilge, Gusher Manual bilge and sump drain have Marleon ball valves installed. Basically with this I can seal up everything if the need arises.

Another concern with the ball valve idea is whether or not ABYC has any issues with this installation. I try to adhere to current ABYC standards with all installs; if I use double hose clamps on both ends I can’t see anything in the regs that presents an issue, unless I’m missing something.
 
1 - 20 of 28 Posts
Top