| Author |
Message |
    
john roe
New member
Username: maverick44
Post Number: 3
Registered: 12-2008
| | Posted on Wednesday, January 28, 2009 - 09:44 am: | 
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I have twin 671 TIBs in a 44' sportfish. Motors were majored 150 hrs ago. Stbd engine has been smoking, even after running at cruise for extended periods. Detroit mechanic found bad injector and replaced. Smoking problem persisted. Mechanic returned to do compression checks on all cylinders. Readings on all cylinders were within 6 pounds of 475 psi - mechanic said these were readings of a new engine and thereby dismissed any thoughts of blow-by. We still do not know why this engine still smokes. Could there be slop in the wrist-pin on the piston? Could a blower be causing this? Any help would be appreciated. |
george sincox
Member
Username: sinner
Post Number: 4
Registered: 11-2008
| | Posted on Wednesday, January 28, 2009 - 10:40 am: |
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john
had a 692 majored last year and had to go thru 12 plus injectors to get 6 good . reliabuilt parts have issues . i could tell when one went bad when i saw smoke and slight fuel out the exhaust port |
john roe
Member
Username: maverick44
Post Number: 4
Registered: 12-2008
| | Posted on Wednesday, January 28, 2009 - 10:50 am: |
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Thanks much George...My mechanic, a life-long Detroit guy, said he used to have a shop that would do a full test on fuel injectors checking all the specs, but that shop is no longer in business...He said in a perfect world, you would replace all of them with a matched set of injectors, but it's unnecessary and costly |
MARVIN PIERCE
Advanced Member
Username: marv
Post Number: 278
Registered: 09-2001
| | Posted on Wednesday, January 28, 2009 - 05:24 pm: |
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WHAT COLOR SMOKE? UNDER LOAD OR AT IDLE |
john roe
Member
Username: maverick44
Post Number: 5
Registered: 12-2008
| | Posted on Thursday, January 29, 2009 - 07:03 am: |
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No smoke at all at cruise speed, but starts to smoke a few minutes after bringing back to idle speed. There is also a minute fuel slick coming out the exhaust port at idle. The smoke appears to be blue. Thanks Marvin |
MARVIN PIERCE
Advanced Member
Username: marv
Post Number: 279
Registered: 09-2001
| | Posted on Thursday, January 29, 2009 - 12:55 pm: |
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good possabity that you have glazed liners.have your mechanic remove air box covers and turn engine by hand and inpect each liner,if glazed they will have a gold color on the cyl walls. |
john roe
Member
Username: maverick44
Post Number: 6
Registered: 12-2008
| | Posted on Thursday, January 29, 2009 - 02:49 pm: |
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If they are glazed, presumably that means the liner would have to be replaced? |
MARVIN PIERCE
Advanced Member
Username: marv
Post Number: 280
Registered: 09-2001
| | Posted on Thursday, January 29, 2009 - 06:25 pm: |
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replaced or honed out |
john roe
Member
Username: maverick44
Post Number: 7
Registered: 12-2008
| | Posted on Thursday, January 29, 2009 - 08:38 pm: |
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So, is your best guess that the smoke is unburned fuel or oil, Marvin? |
MARVIN PIERCE
Advanced Member
Username: marv
Post Number: 281
Registered: 09-2001
| | Posted on Friday, January 30, 2009 - 01:29 pm: |
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WELL YOU NEVER DID TELL ME WHAT COLOR SMOKE BUT I ASSUM ITS WHITE AND THAT WHOULD BE UNBURNED FUEL. |
thurman hill
New member
Username: woodenboater
Post Number: 2
Registered: 02-2009
| | Posted on Tuesday, February 03, 2009 - 01:09 pm: |
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He said it was blue, Marv, in the post just after your first one. Blue means you are burning oil. Glazed cylinders or worn/broken rings would cause that. |
thurman hill
New member
Username: woodenboater
Post Number: 3
Registered: 02-2009
| | Posted on Tuesday, February 03, 2009 - 01:14 pm: |
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And I forgot... Yes, a bad seal on a turbo can let oil into the intake and cause blue smoke. If it's truly oil smoke, the exhaust will also smell different than the non smoking engine. |
john roe
Member
Username: maverick44
Post Number: 8
Registered: 12-2008
| | Posted on Tuesday, February 03, 2009 - 01:57 pm: |
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Thanks for your input Thurman |
jeff fisher
New member
Username: jeff_fisher
Post Number: 3
Registered: 06-2008
| | Posted on Thursday, February 12, 2009 - 07:52 pm: |
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hey guys i have 2 671 low profile 400 hp engines i cant find a pair or alternator brackets in the whole world can anybody help me out,its to the point i dont care how much they cost, i just restored a 34 striker offshore fishing machine and 2 brackets are delaying me and im losing sleep over nite. thanks jeff fisher. |
Dave Baldi
New member
Username: teezer38
Post Number: 1
Registered: 03-2009
| | Posted on Sunday, March 01, 2009 - 09:11 pm: |
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JOHN, I HAVE THE SAME PROBLEM WITH ONE OF MY
671 TI'S.BLUE SMOKE AT START THEN GOES AWAY WHEN IN GEAR.ENGINE SEEMS TO RUN GOOD.COMPRESSION CHECKED GOOD ALSO.REPLACED TURBO RECENTLY ALSO,SO THE SEAL SHOULD BE GOOD.TESTED INJECTORS-GOOD.MECHANIC IS STUMPED AND SO AM I.
MARVIN,IS IT POSSIBLE TO STILL GET GOOD COMPRESSION READINGS WITH GLAZED LINERS OR CRACKED RING? |
john roe
Member
Username: maverick44
Post Number: 9
Registered: 12-2008
| | Posted on Monday, March 02, 2009 - 11:20 am: |
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Dave-
Strangely the smoke goes away while at cruise, but returns about 5 minutes after coming back to idle - not sure if you are experiencing the same thing or not...Let me know |
Dave Baldi
New member
Username: teezer38
Post Number: 2
Registered: 03-2009
| | Posted on Monday, March 02, 2009 - 01:46 pm: |
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JOHN-
LIKE I SAID, SMOKES AT IDLE NOT IN GEAR.SMOKE GOES AWAY IN GEAR AND AT CRUISE.SMALL FUEL SLICK ALSO AT IDLE.THIS HAS BEEN GOING ON FOR 2-3 YEARS NOW.MY MECHANIC SAYS DONT WORRY, BUT IT BOTHERS ME.
I HAVE NOT PULLED MY AIR BOX COVERS YET AS THEY ARE NOT EASY TO GET AT.THE EXHAUST MANIFOLD NEEDS TO BE PULLED TO HAVE ENOUGH ROOM.
SEEMS TO ME, COMPRESSION WOULD BE LOW IF THERE WAS A CYLINDER ISSUE? I DONT KNOW IF IT COULD BE A BAD VALVE SEAL LETTING OIL INTO THE EXHAUST? I'M SURE MARVIN COULD CHIME IN? |
john roe
Member
Username: maverick44
Post Number: 10
Registered: 12-2008
| | Posted on Monday, March 02, 2009 - 02:08 pm: |
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Same thing I have - a little slick out of exhaust port. I had compression in the "new" range on every cylinder. The only thing we haven't checked is the possible "glazing" of liner(s) and the turbo seals. I suspect that will be the next thing we check. Blue smoke is indicative of oil burn; which is bothersome to me |
john roe
Member
Username: maverick44
Post Number: 11
Registered: 12-2008
| | Posted on Tuesday, June 02, 2009 - 07:36 am: |
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Finally discovered the problem on last cruise. Engine was only running at 110 degrees even after cruise. Suspected a thermostat stuck open, and upon removal, confirmed that it was in fact stuck open with a piece of debris. Smoke the result of operating temp severely low |
Jimmy Graves
Member
Username: jimg4652
Post Number: 34
Registered: 11-2008
| | Posted on Tuesday, June 02, 2009 - 04:07 pm: |
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Cool, I learned something new. Thanks for the update! |
