Reply
 
Thread Tools Display Modes
 
Old 12-02-2013, 08:40 AM   #1
Veteran Member
 
Francois's Avatar
 
City: San Antonio, Boat is located in Corpus Christi
Country: USA
Vessel Name: Bluebonnet
Vessel Model: Chris Craft Constellation 500
Join Date: Nov 2013
Posts: 77
Detroit 6V92 - Hard to Start

Any idea why one of my Detroit diesel engine is hard to start after one month of rest?

My Port engine starts first time (no wait). Now my SB engine will start after several long attempt, then with some "puff" will slowly get to throttle RPM. Once done, all is fine and they both operate the same (Oil & Temp).
__________________
Advertisement

Francois is offline   Reply With Quote
Old 12-02-2013, 09:26 AM   #2
Guru
 
City: Carefree, Arizona
Country: usa
Vessel Name: sunchaser V
Vessel Model: DeFever 48
Join Date: Apr 2008
Posts: 6,380
It sounds like a fuel problem. Air in the line from drain back. I assume it starts ok after an hour, day or week but not after a month?? Both engines are fed from same manifold and tank?? If you go to boat diesel with same question they will suggest to you the steps needed to trace the problem.
__________________

sunchaser is online now   Reply With Quote
Old 12-02-2013, 10:38 AM   #3
Senior Member
 
cafesport's Avatar
 
City: Miami
Country: USA
Join Date: Jul 2013
Posts: 492
Quote:
Originally Posted by Francois View Post
Any idea why one of my Detroit diesel engine is hard to start after one month of rest? My Port engine starts first time (no wait). Now my SB engine will start after several long attempt, then with some "puff" will slowly get to throttle RPM. Once done, all is fine and they both operate the same (Oil & Temp).
You haven't provided enough info for a proper evaluation. It could be anything from a weak battery bad fuel corroded injector tip or even a stuck ring. Boat diesel is a good Detroit resource you may want to check out.

Via iPad using Trawler
__________________
Via iOS.
cafesport is offline   Reply With Quote
Old 12-02-2013, 04:45 PM   #4
Guru
 
River Cruiser's Avatar
 
City: UMR MM283
Country: US
Vessel Name: Northern Lights II
Vessel Model: Bayliner 3870
Join Date: Jan 2013
Posts: 1,228
It's loosing it's prime, have you checked for fuel dilution in your lube oil? Could be a external leak between supply pump & fuel galley or a crossover line or bad injector which would show up in a oil analysis. Good luck
__________________
Ron on Northern Lights II
I don't like making plans for the day because the word "premeditated" gets thrown around in the courtroom.
River Cruiser is offline   Reply With Quote
Old 12-02-2013, 06:08 PM   #5
Veteran Member
 
Francois's Avatar
 
City: San Antonio, Boat is located in Corpus Christi
Country: USA
Vessel Name: Bluebonnet
Vessel Model: Chris Craft Constellation 500
Join Date: Nov 2013
Posts: 77
Thanks for all for your answers

Sunchaser, your assumption is correct. My engine starts just fine the next day or couple of days. It is after one month that the difficulty occur (for a non mechanic, that is bizarre !!). After it started, I can run these engines with 10+ hours non strop with no issues.
Both of my engine run on different tanks and I think manifold as well. Do you think I can "bleed" the return fuel line?

Cafesport, if I had bad fuel, would this engine operate with "hiccup" while running? (which is not the case). For the corroded injector tip (which they may be rusted after 28 years of operation...

River Cruiser, I think I will try the oil analysis and see... (good idea)
Francois is offline   Reply With Quote
Old 12-02-2013, 09:50 PM   #6
Senior Member
 
cafesport's Avatar
 
City: Miami
Country: USA
Join Date: Jul 2013
Posts: 492
Quote:
Originally Posted by Francois View Post
Thanks for all for your answers Sunchaser, your assumption is correct. My engine starts just fine the next day or couple of days. It is after one month that the difficulty occur (for a non mechanic, that is bizarre !!). After it started, I can run these engines with 10+ hours non strop with no issues. Both of my engine run on different tanks and I think manifold as well. Do you think I can "bleed" the return fuel line? Cafesport, if I had bad fuel, would this engine operate with "hiccup" while running? (which is not the case). For the corroded injector tip (which they may be rusted after 28 years of operation... River Cruiser, I think I will try the oil analysis and see... (good idea)
Your engines are kind of unique in that they are 2 cycle and there is no need to bleed them once the 2 fuel filters are full. You can just roll them over and they should care of themselves.
Healthy 6v92s emit a steady growl and should have no hiccups. If your engines harmonic beat sounds like a bass a nova you have a problem. You mentioned smoke no? What color and for how long? 28 calendar years equals how many engine hours for these engines? Oil analysis might also offer some clues.

Via iPad using Trawler
__________________
Via iOS.
cafesport is offline   Reply With Quote
Old 12-03-2013, 06:40 AM   #7
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,537
I would look for a tiny air leak, or the fuel supply check valve is gunked after 28 years .

DD sells a small hand pump that can pressurize the system , so air leaks become fuel leaks , lots easier to locate.

About $70.
FF is offline   Reply With Quote
Old 12-03-2013, 08:03 AM   #8
Veteran Member
 
Francois's Avatar
 
City: San Antonio, Boat is located in Corpus Christi
Country: USA
Vessel Name: Bluebonnet
Vessel Model: Chris Craft Constellation 500
Join Date: Nov 2013
Posts: 77
Cafesport, smoke is white for about 8 minutes after I start them. The hours is about 2800 each.
I'll look into oil analysis and replace my fuel filters.
Thanks
Francois is offline   Reply With Quote
Old 12-03-2013, 11:20 AM   #9
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,724
FF,
Thanks for the tip. I may try that in the spring for my fueling problem that I think is still not solved. Would it work w a regular Bosch system?
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 12-03-2013, 12:08 PM   #10
Senior Member
 
cafesport's Avatar
 
City: Miami
Country: USA
Join Date: Jul 2013
Posts: 492
Quote:
Originally Posted by Francois View Post
Cafesport, smoke is white for about 8 minutes after I start them. The hours is about 2800 each. I'll look into oil analysis and replace my fuel filters. Thanks
What is the temperature where you leave the boat ( maybe try a heater in the er next time).White smoke could be a number of things. Any loss of coolant, can you smell coolant or fuel in the exhaust, any sheen on the water? 2800 hours depending on the hp rating could mean you are past due for some replacement parts. Probably best to draw some oil and get it analyzed before you begin any disassembly. Do the engines sound the same once they get up to temp? Do they both pull max rpms. Should have probably asked this first but has anyone done anything before you had this problem?

Via iPad using Trawler
__________________
Via iOS.
cafesport is offline   Reply With Quote
Old 12-03-2013, 12:20 PM   #11
Guru
 
City: Fort Myers
Country: USA
Join Date: Jul 2013
Posts: 956
"2800 hours depending on the hp rating could mean you are past due for some replacement parts"

That is what I was thinking, when they get tired they take a bit to light off and they smoke. Check fuel system out completely, but also might want a DD mechanic to do a full review.
Marlinmike is offline   Reply With Quote
Old 12-03-2013, 02:07 PM   #12
Veteran Member
 
Francois's Avatar
 
City: San Antonio, Boat is located in Corpus Christi
Country: USA
Vessel Name: Bluebonnet
Vessel Model: Chris Craft Constellation 500
Join Date: Nov 2013
Posts: 77
Cafesport, no coolant lost and smoke does not small coolant nor fuel. Before I bought the boat a couple of months ago, the engines were professionally maintained and the survey came out good.
I'll just see what the oil analysis says.

Thanks for your guidance !
Francois is offline   Reply With Quote
Old 12-04-2013, 07:34 AM   #13
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,537
2800 hours is nothing or time for an inframe , mostly depending on how hard they were run.

At 1800rpm its nothing , but if the cruise was 2100 full tilt with turbo and after coolerto the fish killing spot , ideling for hours trolling then on the pin home, an in-frame kit is about $1200 or so.Install $5K +

The engine will need to be lifted but not removed for the overhaul.

To rebuild it it will need to be removed .

Time smoking is not the thing to observe , coolant temperature is.

If you start up , isle for a min or so then run 800RPM till the water is 120F , 1200rpm till 140F , then 1600, when (at what temp) does the smoke clear?

IF it takes 160F to clear , its time for those new cylinders!
FF is offline   Reply With Quote
Old 12-04-2013, 12:50 PM   #14
Guru
 
River Cruiser's Avatar
 
City: UMR MM283
Country: US
Vessel Name: Northern Lights II
Vessel Model: Bayliner 3870
Join Date: Jan 2013
Posts: 1,228
Not to hijack the thread but I will, I worked for several years for a contractor that had a spread of Terex scrapers & dozers all Detroit powered. The death knell for them was overheating, the scrapers were almost always running against the governor when in the cut loading, on the haul road & at the fill area. They were always on the edge of overheating depending on the ambient temp, because of this someone in the office got the idea of installing smaller injectors in the 12v71 in one of the scrapers. What also made this seem like a good idea I guess was that fuel had taken a big jump in price. The way it worked out was 5 scrapers that still had the N70 injectors were running slower until they could pass the slower one with the N65 injectors. There was no appreciable difference in engine temps but there was a decrease in loads per day & none of the operators wanted to run the slower one. A Detroit mechanic told me that they "run the best just before they blow up" of all of them I worked on I never saw one have a catastrophic failure, most just got hard to start & low on power. They are sensitive to the quality of air filters because being a 2 stroke they use twice as much air for combustion as a 4 stroke. If we got 2000 hours on the 12v71 this was considered pretty good. Some of the other smaller Detroits did much better almost as good as the Cats;-)
__________________
Ron on Northern Lights II
I don't like making plans for the day because the word "premeditated" gets thrown around in the courtroom.
River Cruiser is offline   Reply With Quote
Old 12-04-2013, 03:14 PM   #15
Veteran Member
 
Francois's Avatar
 
City: San Antonio, Boat is located in Corpus Christi
Country: USA
Vessel Name: Bluebonnet
Vessel Model: Chris Craft Constellation 500
Join Date: Nov 2013
Posts: 77
Good info river cruiser, I will change my air filters and discuss the injector idea with a Detroit mec.
Thanks
Francois is offline   Reply With Quote
Old 12-05-2013, 07:50 AM   #16
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,537
I will change my air filters and discuss the injector idea with a Detroit mec.
Thanks

The DD dealer will have a bunch of charts showing HP/fuel flow at various RPM with a number of different injectors.

LOTS to chose from .

For any 2 stroke DD the goal is to operate at 60% power, and up.
FF is offline   Reply With Quote
Old 12-26-2013, 04:35 PM   #17
Guru
 
City: Venice Louisiana
Country: United States
Join Date: Dec 2013
Posts: 1,097
White smoke for several minutes, and slow to start is almost always caused by air in the fuel intake line. It takes awhile to get the fuel back to the injectors and then awhile longer to clear out the air in the injectors.
kulas44 is offline   Reply With Quote
Old 12-26-2013, 08:18 PM   #18
Guru
 
C lectric's Avatar
 
City: Somewhere
Country: , Canada
Vessel Name: Island Pride
Vessel Model: Palmer sedan 32'
Join Date: Oct 2007
Posts: 1,874
Check for a fuel line check valve. Some D.D. had them and when they fail to close properly will allow slow bleed down of the fuel in the lines and the return line which allows air in. Then the fuel pump must reprime the system and clear the air which makes for a lot of cranking and bumbling.

Although a totally different engine mine has a check valve in the return line and once I found and changed the old valve, the restarting after a long sit time was totally different.
C lectric is offline   Reply With Quote
Old 12-27-2013, 05:02 AM   #19
Guru
 
City: Port Vila
Country: Vanuatu
Join Date: Nov 2010
Posts: 628
The reason DDs have a blower/compressor/supercharger is not to make them go fast but because 2 stroke engines require mechanical forced air induction to start (larger ships do it with fans which are stopped after engine is running). A look at the blower and coupling might be a good idea as well.
Nightcap is offline   Reply With Quote
Old 12-27-2013, 07:12 AM   #20
Senior Member
 
City: Green Cove Springs, Florida
Country: USA
Join Date: Feb 2012
Posts: 211
Send a message via Skype™ to bglad
A customer had a similar problem with his Hatteras. They found a leak in the fuel system from the tank manifold. Some of the fuel valve stems were leaking. If your tanks are located lower than the engines it could be the same for you.
__________________

bglad is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 09:46 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012