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Crusader 8.1 problems

Old 06-11-2019, 01:32 PM
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Default Crusader 8.1 problems

OK, twin Crusader 8.1 MPI's. Starboard running good, not so good with port. Port engine running real rough, so I drained my Racor, LOTS of water and trash. Ran the engine some more and drained Racor again with lots of water and trash.
In addition to engine running real rough, I turn the key off and engine keeps running. Turn off the batteries and engine keeps running. Finally, turn off the fuel and after a minute or two, engine shuts down.
Talked to a mechanic and hopefully, he will be able to get around to me in the next week or two. (they are all busy). When I told him about the engine not cutting off, he immediately said, due to all the water in the fuel, I probably have a couple of stuck valves and worst case scenerio, I may need to have the heads redone.
OK, before he gets to the boat, I get my tanks polished. Lots of water and trash in the port tank. Not as much water and very little trash in the starboard tank.
My question....is there any kind of lubricating fuel additive I can add to my tank that might free up stuck valves, assuming the mechanic is right. It would be great if a good shot of Marvel Mystery Oil (or something similar) would clear up my problems.
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Old 06-11-2019, 01:33 PM
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You turned your battery switch off with the engines running?
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Old 06-11-2019, 01:36 PM
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Yes, I did. Turning the key off and it kept running. Just looking for someway to shut it down. I mentioned that to the mechanic and he didn't say anything about it.
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Old 06-11-2019, 02:02 PM
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Yea, not a good idea to shut the battery switch off on a running engine. You could damage the alternator or any of the associated electronics. The battery acts as a HUGE buffer for the electrical system. Shutting the fuel off is the right way, but it may not shut down immediately because of the pressure in the system. Will eventually though, or you have a cool engine that all of us should adopt (one that doesn't need fuel to run). I'd get good gas in it and just run it. And change ALL the fuel filters, as there are probably some more downstream than just the Racors.
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Old 06-11-2019, 02:06 PM
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Originally Posted by chuck34 View Post
Yes, I did. Turning the key off and it kept running. Just looking for someway to shut it down. I mentioned that to the mechanic and he didn't say anything about it.
Just grab the coil wire and give it a good yank!





Don't do this without thick rubber gloves!
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Old 06-11-2019, 02:14 PM
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OK, I hear you about the alternator. Access to the engines....ain't easy.

Back to my original question....is there some lubricating additive I can add to my fuel that might free possible stuck valves?
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Old 06-11-2019, 02:17 PM
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I wouldn't have any trouble adding Marvel Mystery Oil to the gas. I've used it numerous times. I do believe it is good at lubricating things like the fuel pumps, so it may help any valve issue. I just wouldn't guarantee any results.
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Old 06-11-2019, 03:56 PM
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Never heard of "stuck valves" causing an engine to run on.
The term for an engine running on is "Dieseling" and as in the name the engine is dieseling, no spark, and a lot of times it's one or more cylinders.
One cause is carbon build up acting as an igniter.
Another is idling too high.
Did you try shifting into gear to put a load on the engine?
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Old 06-11-2019, 06:24 PM
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Yes, I am well aware of dieseling. When I turned the switch off, there was no difference at all and I think I did try putting the engine in gear. Idle speed is as alway, around 700 or so.
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Old 06-11-2019, 06:32 PM
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Actually, I'm starting to think I may have some kind of short in my ignition switch.
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Old 06-11-2019, 07:00 PM
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Was the engine running smooth? Doesn't sound like stuck valves to me, look for a new mechanic.
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Old 06-11-2019, 07:10 PM
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Originally Posted by chuck34 View Post
Actually, I'm starting to think I may have some kind of short in my ignition switch.
probably.

with all that water the rough running is probably caused by water in the fuel system, no stretch there. When the racor fills up the next line of defense is the fuel control cell. When that fills with water it goes straight to your injectors.

the fuel control cell has a drain on the bottom of it. If it’s gotten that bad you probably need to drain it, separate the bowl, replace the internal filter, and remove the fuel rail and injectors, and send the injectors off to be cleaned. Then fix whatever was causing water to get into your fuel tank. Most likely culprit is the fill o-ring.

One nasty secret about 8.1’s is the pistons are prone to cracking from a partially clogged injector on one cylinder. If you have trash in your fuel system i’d clean the whole system out to be safe.


Last edited by dell30rb; 06-11-2019 at 07:16 PM.
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Old 06-11-2019, 07:21 PM
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Originally Posted by mikie View Post
Was the engine running smooth? Doesn't sound like stuck valves to me, look for a new mechanic.
I've said from the beginning, engine running very rough.
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Old 06-11-2019, 07:42 PM
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Stuck valves still wouldn't cause the engine to keep running when you turned off the ignition. Running rough is more then likely because of the water in the fuel. Running after you turned of the key is an electrical problem. Turning off the batteries while the engine was still running, and it keeping on running means your alternator was working (hopefully it still is).
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Old 06-11-2019, 08:05 PM
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No question that water and trash in my fuel is the culprit for rough running.
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Old 06-11-2019, 08:25 PM
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There's no way you have stuck valves. Its from the water. Why wont it shut off? Just one engine or both?
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Old 06-11-2019, 09:15 PM
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Originally Posted by Harleys Gone View Post
There's no way you have stuck valves. Its from the water. Why wont it shut off? Just one engine or both?
as mentioned in my first post, port engine running rough. Starboard engine is good. I had the tanks polished. Port had a lot of water and a lot of trash. Starboard, not as much water and very little trash
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Old 06-11-2019, 09:15 PM
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While you are pondering the mysteries of the Engine That Stays Running, it's important to figure out the source of all that water that made it into your tank so that doesn't keep causing major trouble. The most likely one is usually a cracked or missing fill cap O-ring...with a few other more remote possibilities like bad fuel source, leaking tank sender gasket, vent fitting or sabotage.

Since you had the fuel "polished" I hope there was no E10 gasohol in there. That would usually require full removal and replacement of the contents.

You don't by any chance have a relatively low -quality Perko battery switch? Whatever make, if it is held together by screws and not rivets ( like Perkos), I suggest you disconnect at the batteries and check the inside of that switch (... after confirming there are no wires attached to wrong battery or switch terminals.) What is wired directly to the battery bypassing the switch? Have you reconnected the batteries or other wires recently?

I'm not very familiar with alternator wiring but since some have a +sense wire connected to the battery it just ...may... be possible an internal problem there may be a source of ignition power with key and battery switches off.
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Old 06-12-2019, 01:43 PM
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Originally Posted by dell30rb View Post

the fuel control cell has a drain on the bottom of it. If it’s gotten that bad you probably need to drain it, separate the bowl, replace the internal filter, and remove the fuel rail and injectors, and send the injectors off to be cleaned. Then fix whatever was causing water to get into your fuel tank. Most likely culprit is the fill o-ring.

Ok, my port engine has a water separating Racor filter, that I did replace. My starboard engine, which is running good, I can't find the same kind of Racor anywhere in my engine room. However, there is a Model 110A fuel filter/water separator that is mounted on the engine. It looks to be somewhat smaller than my port Racor. I can't imagine why I would have different filters on my engines. However, there is a chance that there is a 110A filter on the port engine as well, but just getting eyeballs on it is easier said than done.
Any chance that 110A is the fuel control cell you are talking about.
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Old 06-12-2019, 06:58 PM
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Here's the good news. You dont need new engines. Find a good mechanic. Bring him lemonade until 5 then bring him beer. It's all gonna work out.
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