671TIB makes fog and will not start

Starboard engine leaps to life, press start and it is running. Port did that as well when I bought the boat in November, mechanical surveyor recommended that they be tuned, which I had him do. Then it seemed Port engine started to crank a bit before starting, longer each time. First 2-3 seconds, then 5 seconds, then 5 seconds wait 30 seconds and then it would start after a few seconds. Now it does not start. I have block heaters and even turned up to 120 degrees over night still no joy.

While cranking -- a lot of fog (I assume diesel) immediately comes out the hoses that come from block into an antifreeze bottle, blow by capture I was told, to keep oil out of bilge.

This engine is furthest from start batteries, have not been able to really check connections but initial observations look fine.

Thank you in advance for help.

Hi crabber 50, just a guess but check to make sure your electric stop solenoid is coming all the way back to start position. It's mounted on the governor.
Charlie w

Hi,

Sorry you're having problems. I probably won't have an immediate solution for you but maybe with some back and forth we can figure it out. I like CHARLIE W's suggestion and checking the engine stop lever operation is a good starting point.

If that checks out ok then I would next want to know if the blower is turning while you're cranking. If the blower drive has stripped, it won't get any air to start. Also, I see that it is a TIB...The B stands for Blower BYPASS. If that bypass valve sticks open for some reason then it would be similar to the blower not turning and would be starved for air during start up.

The hoses you mention...That sounds like the air box drain system. Nothing but a very small amount of engine oil should be coming from those if the air induction is working properly. The air box should have a positive pressure from the blower and should not allow raw fuel to enter through the ports. That is why I am asking about how the blower is operating. I would suspect that bypass valve being "sticky" and, if so, I would replace it.

Try to determine if it is actually fuel vapor you're seeing and not water. With the engine not starting, limit your cranking while you are sorting it out and leave the seacocks closed so sea water can't back up in the exhaust and flood the cylinder head. BUT DON'T FORGET THEY ARE CLOSED!!! Red tag the helm with a note to remind yourself.

The "nice" thing about these engines is that there is no ignition system to worry about and they pretty much NEVER jump time. So a no start typically boils down to either lack of fuel or lack of air.

You spoke of fuel so I sort of went down the lack of air path. But, the gradual onset to the problem might suggest a lack of fuel. That is something to consider and I would ask you if both engines feed from the same tank(s)? But I'll stop now so as not to confuse you and see what you come up with as to the stop lever and blower operation.

Good luck.

What does the tune up guy say? Sounds like the trouble started after he worked on them.

CASTLE_CAPE said:

What does the tune up guy say? Sounds like the trouble started after he worked on them.

Click to expand...

He says that he adjusted valve clearance etc. and that the issues are unrelated to that, he would have to look at it to see what broke. He is over 3 hours away from the boat. Willing to come out --but nor sure I am ready to pay for that...yet.

CHARLIE W said:

Hi crabber 50, just a guess but check to make sure your electric stop solenoid is coming all the way back to start position. It's mounted on the governor.
Charlie w

Click to expand...

Thanks Charlie, Will do that, not back with boat for two weeks but wanted to create my list and read up in the manuals so I know how to do things. Now that I know there is a electric stop solenoid I'll find and study it in manual as well as the other recommendations.

Thanks again. will be posting results.

Hello again JMGO,

Looking forward to getting through this with you all, There are two fuel tanks that are selectable via Y valve, each engine is using it's own. Filled them both up about 10 operating hours ago. Pretty sure that it is fuel vapor, it is very odd as it looks like fog from a fog machine, at first thought it was smoke, it just hangs, engine blowers removed it then cranked the engines from engine room and notice it comes out immediately and is pretty thick. so I stopped all attempts to start. Was wanting to exercise the engines before my trip. So I will read up on how to check the Solenoid, blower is spinning or not, and bypass valve.

Thanks

Fuel vapor , white fog out the air box drains means unburned fuel. Lack of air.
The emergency shut down has been tripped (if the engine has it) or blower drive is stripped, as mentioned. Some how you are NOT getting air into that engine.
Your problem is not with the shut down solenoid that is hooked to the governor.
You are getting plenty of fuel .

Unlikely to be your issue I hope, but if the mechanic incorrectly adjusted the valves there is a chance that they have been gradually 'burning' and that you have lost a lot of compression. That would explain the gradual nature of your problem developing. Not sure how that creates your 'fog', but the problem beginning immediately after the valve adjustment is a bit suspicious at least.

yes, the "gradual nature" is harder to explain and,
the "valve adjustment" is very suspicious .

The electronic manuals I have are from 1974 and the engines are 1989-90, found manuals I can order on this site, that hopefully show the Bypass, the manuals I have do not. If the blower wasn't turning then would the engine still be getting fuel? It seems the fuel pump and water pump run off of the blower? If the bypass was failing (sticking?) I'm assuming it would be on the pressure side of the blower, if it was stuck open then the cylinders wouldn't clear and could have the issue?

Yes the fuel pump is probably mounted on the blower, DD has many options for mounting driven accessories .
I have never worked on or even seen a by-pass blower setup, if this is keeping the engine from starting then they do not operate how I always "assumed" they did
From what I read your TIB has a "Maxi by-pass blower" , maybe someone can explain that operation.

A few pics, all I could find. Supposed to be a TIB .
http://www.goldcoastpower.com/gallery.cfm?product_ID=87129

Yes, you make a good point about the fuel pump. And, since I'm viewing your photos on my phone and I'm not getting a "cleat picture" of what you have there, I will speak to the bypass operation.

A blower bypass is just that...a valve in a separate passage for boost air to be able to "go around" the roots vanes (rotors). The supercharger, being gear driven, is limited in volumetric efficiency at higher engine load demand and becomes a "road block" to the air coming from the extremely efficient turbo spinning at high speed. So, at a given boost pressure the bypass valve opens and the boost air bypasses the rotor vanes. What surprizes most people is just how small the valve and passage actually is.

Just look for a device, just to the rear (typically) of the blower inlet, that is bolted to the blower. The ones I'm familiar with are about 2" tall and about 1 1/2" in diameter. It may have a hose going to it from a Y In the air inlet ducting above the blower.

I have heard of internal ones but have never seen one. If yours is internal you may need to find the documentation on your blower to find out how it's serviced.

If it sticks open the blower pumps air out the valve, upward, and not to the engine air box.

Back at the boat and found/figured out where the bypass valves were. Removed Air Box Door Housing to inspect orientation of valves. Valves were closed, unclear to me how to service so I reassembled hoping that the valves closed during disassembly. The Engine started right up. So I am assuming that the valves had stuck open and had closed somehow since then? Any ideas on how to service these?

This may sound dumb but where do the two large braided lines lead? Are they the "bypass" lines going to the air box? I've never seen a bypass setup like this. If the air inlet from the turbo is just out of the photo on the bottom, then that must be how this is set up. I believe it is a system that would also act as a "waste gate" to prevent over pressure. I think that is what that black check valve looking thing is that you can see between the two "boxes"

OF COURSE, it was built by someone smarter than me. So, I have to say, that if it works as I think it does, it is pretty ingenious. Only one problem.....

....One reason I would see that would make it superior to the internal blower bypass is that it looks as if when the bypass valve(s) stick...the engine should still be able to start!!

I mean, it's all located on the inlet side of the blower.

Although, I suppose that if the valves hung open, then that would allow the blower to sort of "feed itself in a circle" by pumping air to the airbox but then drawing the air right back out of the airbox!

BUT...wouldn't a couple of check valves solve THAT problem?

Do those braided lines HAVE check valves associated with them? And, if so, could THEY be stuck open too?

This is all speculation on my part but, like I said, I would TRY and help you figure it out.

As far as servicing those pistons....do I see bolts holding them in? Couldn't you just unbolt them and slide them out?

You may want to check the turbo compressor wheel seal. It looks as if the rotors are getting good and oiled up. That would be turbo seal or it could be the blower rotor seals are weeping a bit. But it looks like it is coming from the turbo because the box looks wet and that would explain why the valves may be sticking open.

It looks like an emergency air shut down to me.
What else would the morse cable be for?
It got tripped and the engine wouldn't start, that's normal, until it is manually reset .
Follow the morse cable, see where it goes.
Somehow it can be reset with out taking anything apart.

I think he would have said if the doors were tripped. I see the reset cam and he never mentioned moving that. But I guess we'll have to see what he says.

jgmo , yes, after rereading crabbers last post I think you are correct.

So the ends of the braided lines we do not see in these pics, they go directly into the airbox, or the airbox side of the blower? And at a certain boost the valves open and boost goes "around" the blower and directly into the airbox? If so then I understand the no start. Never seen this system before and I can't see all of it now, so I have no idea how to service it.

Seems to me that the four bolts....one on each side of each valve....come out and the whole shebang is in your hand in about 2 minutes.

Is it simple? Pistons with springs holding them closed until boost pressure
from the turbo shoves them open ?
Maybe just gummed up from too much oil.

Yep, that's the way it was on all the V engines I worked on. Only we found that cleaning them wasn't always reliable. We learned to just put in a new valve in place of one that was sticking. Although, if I would have had my ultrasonic cleaner back then, I would have given that a try first.

Sorry for the slow reply, wanted to check pictures and video I took while the engine did not start. Started to think I must be wrong and the shut down was closed. However after review it is clear that the shut down was in fact open it is easy to see its condition in the photos. That makes me feel better even though it was checked I started to second guess myself.

When removing the bolts that appear to hold the valves in I could see sealant, there are also flats that must be for a large wrench, was afraid to monkey with it, but may have to, or if I remove fittings on bottom can I access that way? I will check.

jgmo, I agree with your assessment of the braided lines, I do not think they have check valves, what type would I add? Also agree that it must have stuck and recirculated, it is all I could come up with.

Let me know if you guys want any other pictures, plan on taking it apart again today and seeing if I can get access to the pistons.

Can't thank you guys enough, I have learned so much about the engines during this process, THANKS TO YOU GUYS! also bought manuals from this site.

Will let you know if I am able to take apart or not. The other issue is how would I even buy a new piston when I do not even know anything about where these came from?

Hi Crabber50,

Yes, it was never a case of the air doors shutting. That NEVER happens gradually and they usually leak enough air that the symptom is no start with lots of BLACK smoke.

You may have to take the whole air horn back off to get the valves out. I don't see the large flats you're talking about but that might just be the material they used to fabricate this rig. Just don't force anything and I believe you will have good news for us in a bit.

As far as replacing the valves, I would try a phone call to Johnston and Towers if you are really interested in finding some. JT can probably steer you in the right direction. Although, it surely won't hurt to just try cleaning them up and seeing if they hang again. If they do, you already know you can deal with it.

I'm still concerned about the oil I'm seeing and if you do remove the horn again, make sure you check to see if oil is coming from the turbo. YES! MORE PICS! You are NOT bothering us...we LIKE this stuff and it keeps ME off the streets.

I wouldn't put too much thought behind my check valve comment. Like I said...this was designed by someone WAY smarter than I and they may have had a very good reason not to put any there in the first place. Added restriction to air flow (boost) comes to mind right off the top.

Many positive "takeaways" for you so far. As you said, you've learned a lot about the care a feeding of these beasts. You are going to be properly equipped with manuals. You are now a tried and true troubleshooter that has some skills in getting them going that could be invaluable in an emergency situation.

You also now know that your tune up guy didn't screw up and can be trusted.

Standing by.

Here are some close ups of the valves, searched online for the part number you see on top and the eBay item came up. Looking at the eBay item and the sealant, it does not appear these are treaded in. Not sure how tough the sealant is but looks like I could do damage removing them. But not sure they are even an issue, see below.

Update, the bypass valves are closed and the engine was hard to start again. Cranked for 5 seconds, waited 15 seconds, cranked again for 5 seconds and the fog came out the air box drain again! Stopped, went and beat my head against the wall, then turned switches off at helm and back on again. Went back to engine room, started the "good" Starboard engine, 1 second crank and she's running. Let it run for a few minutes, then started Port engine, it cranked just a few seconds and started up.

So, could I have a bad switch or, one of my theories is that this problem on the Port engine could be because it is farther from the batteries then the Starboard. The Batteries are on the outside of the Starboard Engine so likely 6' of battery cable closer. Wondering if the Port is not cranking fast enough to start. Connections on Engine look great, starters look like new. I need to look at battery connections and see the route of the cable, the cables are very heavy gauge, there is also a battery combiner in the system as well.

I am heading down to try it all again carefully, will update tonight

It is starting right up, since there is no ignition and I am getting fuel. Can it even be a switch?

Weird!. Start's right up now you say?
Well, you could be right....it does take a fair amount of cranking rpms to generate enough heat. The white fuel vapor is completely raw, unburned fuel vapor. So, it is either not generating enough heat...at times....or it is not getting any air....at times.

So, the mystery continues.

Do you have the ability to tach the stbd engine cranking rpms and compare that to the port engine cranking speed when the problem occurs? If there is a large difference....say 50 rpm or so....then yes, it could have a start system electrical problem causing slow cranking and thus no heat/fire.

The thing that gets me is that it seems to want to start ok RIGHT AFTER you have been tinkering with the bypass valves. Coincidence? I wonder if the springs in one or both of those valves is weak? I know it's a pain but you might want to consider swapping the ones in the stbd. engine to the port and vice versa. If the problem moves, then it's those valves. If the problem stays put with the port engine then at least you have eliminated that as a possibility.

Used the boat over the weekend and it started right up again, each time I started the Port engine first (the one that had a problem) so that means all four of the last starts were okay. Underway we ran mostly around 1400 RPM but took her up to a little over 2000 for about 5-10 minutes. So, only can hope that it was the bypass sticking and right now it is not.

Do not have a handheld tachometer but I see some online and may pick one up in case this happens again.

Great advice on swapping the valves with the Starboard Engine. I will keep that in mind.

I'll start a new topic for the turbo.

Thanks again