| Author |
Message |
    
JoelHolland
Visitor
| | Posted on Tuesday, April 24, 2007 - 03:11 pm: | 
|
Bought boat in August 06. 1900 hours on engines. Would run 1900 RPM with nasty bottom, dinged prop and added swim platform. Should run 2300-2350 RPM if everything bottom and props and platform fixed/removed. Out of water 100 days, new bottom, new rudder. Will only run 1100 RPM and begins to belch black smoke. Have cleaned inner coolers, turbos and checked air filters. Have replaced old fuel (sucked out by waste company) with new fuel.
Props have been checked and changed for alternate set. Both engines acting identical. If attempt to push past 1100 engines begin to bog. Normal initial white smoke for a moment with fresh start till warm. Minimal blue smoke until warm. Idles wonderfully without smoke when warm. Seems to run normal between 650 RPM and 1100 RPM. HELP, what else to look at? |
MARVIN PIERCE
Advanced Member
Username: marv
Post Number: 141
Registered: 09-2001
| | Posted on Wednesday, April 25, 2007 - 03:43 pm: |
|
ARE YOU SURE YOU PUT THE RIGHT PROPS BACK ON??? WHATS THE NO LOAD RPMS?? |
Dwight Brooker
Member
Username: sailmaster
Post Number: 47
Registered: 05-2006
| | Posted on Wednesday, April 25, 2007 - 04:11 pm: |
|
Have you checked the all the fuel filters and injector? |
Joel Holland
New member
Username: joholland
Post Number: 1
Registered: 04-2007
| | Posted on Thursday, April 26, 2007 - 12:36 pm: |
|
Boat came with 4 blade props already installed. Boat had spare set of 3 blade props in the lazarette. 4 blade props were pulled during bottom job and sent to reputable prop shop. Per the prop shop, no major adjustments were required or made to the 4 blades. Boat was water tested and problem began to occur. 3 blade props were carried to prop shop and evaluated and found to meet required specs for the boat, per the mfg. Boat was pulled and 4 blades were replaced by 3 blades. Problem persists. |
Joel Holland
New member
Username: joholland
Post Number: 2
Registered: 04-2007
| | Posted on Thursday, April 26, 2007 - 12:42 pm: |
|
Fuel filters have been checked and appear to be in good shape. I do not understand how fuel filters could cause an excess of fuel in the cylinders, thus causing the black smoke. The fuel in the filters appears to be fine. We have sucked 400 gallons of fuel out and disposed of (OUCH TO THE TUNE OF $1,000 WORTH OF FUEL). Suction and disposal was another $192.00. But, I digress. The removed fuel did not show any obvious problems of water or discoloration or particulates. Fresh fuel was put in and the boat was run long enough to introduce the fresh fuel to the engines.
NO, the injectors have not been checked yet. That is one of the next items on our list. |
Joel Holland
New member
Username: joholland
Post Number: 3
Registered: 04-2007
| | Posted on Thursday, April 26, 2007 - 01:17 pm: |
|
We are going back over some areas that have already been looked at. We think we may be seeing excessive oil in the blower. We are replacing the bypass valve on the premise that excessive oil being introduced into the air mixture would not be a good thing.
Our next steps will be to check the fuel bypass valve to see if it is stopped up and creating to much pressure which would send more fuel to the cylinders than necessary.
After checking all of the above, we will begin to check all the injectors. Are we missing anything we should be thinking about or looking at.
Turbos work and have been cleaned.
Blowers work and bypass valves are being replaced.
Intercoolers have been cleaned.
Air filters considered.
Fuel problems eliminated.
Props are factory spec.
Engines were aligned and cutlass bearings replaced during bottom job.
New packing and boot installed.
Shaft tower under boat is slightly bent from accident with previous owner that bent rudder shaft and required a new rudder. Accident only caused slight damage to the prop which was repaired by the prop shop.
When shafts were aligned, significant repositioning of the engine was required to achieve alignment. |
MARVIN PIERCE
Advanced Member
Username: marv
Post Number: 146
Registered: 09-2001
| | Posted on Thursday, April 26, 2007 - 06:12 pm: |
|
STILL NEED TO KNOW WHAT THE N/L RPMS IS UESING STATION CONTROLS |
Joel Holland
Member
Username: joholland
Post Number: 4
Registered: 04-2007
| | Posted on Friday, April 27, 2007 - 09:03 am: |
|
Sorry about missing your question. No Load RPM's are 2600. |
MARVIN PIERCE
Advanced Member
Username: marv
Post Number: 147
Registered: 09-2001
| | Posted on Friday, April 27, 2007 - 02:21 pm: |
|
ok black smoke is caused from,lack of air,or over fueling,or over loading. lack of air check for flaper valve on air in let adptor that bolts to top of blower,flaper my have broken pins.next whould be to pull inj and have tested. |
Joel Holland
Member
Username: joholland
Post Number: 5
Registered: 04-2007
| | Posted on Friday, April 27, 2007 - 03:49 pm: |
|
Thank you. I will report back. We will find the problem and the solution and I will make sure that the findings/results are reported. |
Joel Holland
Member
Username: joholland
Post Number: 6
Registered: 04-2007
| | Posted on Friday, April 27, 2007 - 04:15 pm: |
|
Someone has mentioned the fuel return bypass valve and bypass hose. I think the logic is that if the bypass is not functioning, to much fuel is forced through the injector into the cylinder. Would this be a possibility? |
MARVIN PIERCE
Advanced Member
Username: marv
Post Number: 148
Registered: 09-2001
| | Posted on Friday, April 27, 2007 - 06:57 pm: |
|
to much fuel pressure will cause the inj rack to be difficult to operate, it will not cause over fueling. |
Joel Holland
Member
Username: joholland
Post Number: 7
Registered: 04-2007
| | Posted on Monday, April 30, 2007 - 09:46 am: |
|
We are currently replacing the bypass valves in the blowers. They appear to have been allowing oil into the blower. If this does not alleviate the problem then based on everything I am hearing, that pretty much leaves just the injectors. What could or would be wrong with an injector or injectors that would cause this problem. May I also mention again that both engines are acting identically. I cannot perceive any operational differences no matter what I do. |
MARVIN PIERCE
Advanced Member
Username: marv
Post Number: 151
Registered: 09-2001
| | Posted on Tuesday, May 01, 2007 - 06:50 pm: |
|
WITH BOTH ENGINES HAVEING THE SAME PROBLEM,MABEY YOUR NOT GETTING ENOUGH AIR INTO THE ENGINE ROOM.YOU MIT ALSO CHECK THE FUEL TANK VENT HOSE. |
Todd Schreiber
New member
Username: tes
Post Number: 3
Registered: 06-2007
| | Posted on Sunday, June 03, 2007 - 07:20 am: |
|
If both engines display the same problem and this problem only exists under load, then it is probably not a failed component on both engines.
Your initial post sounds exactly like the boat is over propped. What is the size of the boat, length and displacement? And what is the diameter and pitch of the props? What is the transmission ratio? And, did you change the transmissions while you were doing the engine work? If you changed the ratio of the transmissions, then you need to change the props accordingly. |
Joel Holland
Member
Username: joholland
Post Number: 8
Registered: 04-2007
| | Posted on Monday, June 04, 2007 - 09:07 am: |
|
To answer Todd, the transmissions have not been changed. The props were the first place we looked and they have been eliminated as the culprit. |
Joel Holland
Member
Username: joholland
Post Number: 9
Registered: 04-2007
| | Posted on Monday, June 04, 2007 - 09:14 am: |
|
New information: Excessive oil was found in the blower. A new blower is being installed. I intend to change out both blowers. NOW, in the process, it was discovered that the RISER was severely cracked on the port engine. We have not started on the starboard engine yet, so it will not surprise me to find the same thing on the starboard. Diesel Don has taken over the project for any of you in the Southeast that may know of him. He is considered the premier Diesel man in this area and apparently from Florida to Mississippi to Kentucky, etc. He has made more progress in the last 24 hours than has been made in the last 3 months. I will continue to provide a step by step determination. His only comment at this time is that a cracked riser would make it impossible for the turbo to do its job and the engine would be starving for air. |
Ron Creager
New member
Username: awsome
Post Number: 1
Registered: 06-2007
| | Posted on Wednesday, September 05, 2007 - 07:36 pm: |
|
What happened? I have problems with my J&T 671TI |
Joel Holland
Member
Username: joholland
Post Number: 10
Registered: 04-2007
| | Posted on Thursday, September 06, 2007 - 09:14 am: |
|
We are still not finished with the engines, but here is what I have found so far. I did have a couple of injectors not working properly, up to and including a broken push arm on one of the injectors. I may have used the wrong terminology but hopefully you know what I am talking about. Second problem, is my blowers were leaking/allowing oil in and obviously oil does not burn well. Third and maybe as important as anything was a fuel governor mechanism had apparently been removed sometime in the past by a previous owner/mechanic and if the throttles are moved forward even slightly to quickly, the missing governor allows to much fuel to flow into the cylinder before the engine is ready for it. So, once the first two problems were addressed and the third problem was taken into consideration when accelerating, the boat actually ran 33 knots. That is at least until we discovered either a cracked head or blown head gasket and water in the oil. So at this point, I have one engine that seems to be in good shape - the port. I have one engine that may have actually seized up. My lack of power did turn out to be almost EVERYTHING that anyone and everyone said it could possibly be. I think usually it is one of the problems, not all of them at the same time. I would look at the injectors first. I would make sure the governor and fuel delivery system was all working properly before I looked at anything else. If you read above, we obviously looked very closely at many other things before we looked closely at the fuel delivery. We should have started with fuel delivery. Oh, by the way, did I mention that almost as soon as we achieved 33 knots, I lost a turbo on the port engine. Oh well, B.O.A.T - Bring, Out, Another, Thousand.
Good luck. |
tim colavito
New member
Username: timma
Post Number: 1
Registered: 12-2007
| | Posted on Thursday, December 27, 2007 - 02:00 pm: |
|
I occasionally run a 120ft crew boat with 4 16v92 turbos. We usually run at no more than 1600RPM but have gone through exhaust valves more frequently than should be. More or less RPMs? I've heard both sides. Anyone got any input? |
