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| Engine help and questions on a marine... |
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svubiquitous
New member
Username: svubiquitous
Post Number: 1
Registered: 10-2015
| | Posted on Sunday, October 18, 2015 - 09:37 pm: | 
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We have just come into a new to us Trawler. We have typically been Sailboat creatures and are comfortable working on our Yanmars, Perkins and Kabotas...we now find ourselves with a beast of an entirely different color. We have spent several days trying to find information and assistance as we feel the engine is not performing as we would have expected.
The first thing that we found is the impeller was completely toast. The exhaust system had to be replaced. All of this has been done and there is water now gushing through the water-cooled exhaust.
What we do know:
This is a keel-cooled system
There is oil in it
It cranks up first time every time
It dies after we have run it for about 20 minutes
What we need to know
1. How do you check the coolant on a keel cooled system
2. How do you tell if your oil filter is clogged and needs replacingj
3. What should oil pressure be (ideally) at
idle:
Cruising (5 knots - sailboaters remember  )
Full Throttle
4. What might cause smoke to come from the dip stick (not billowing like an explosion but noticeable to those looking)
5. Is there a strainer that is in the oil pan or is it somewhere easily accessible and should that be changed
6. What temp should the motor be expected to run at
7. What should the ideal RPMS be run at during cruising (vessel is 29 ft with 23 in 3 blade prop)
8. Can the motor be ran to fast or is there a governor
9. What type of mileage might we be able to expect traveling at approximately 5 to 6 knots
10. If I remove the valve covers do I need to replace a gasket upon replacing them covers on the engine
Thank you so very much for taking the time to answer any of the questions - we need all the help we can get!!
Bill and Jess |
jimmys
Senior Member
Username: jimmys
Post Number: 59
Registered: 01-2011
| | Posted on Monday, October 19, 2015 - 03:48 pm: |
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1. Open the Top Tank Cap and check the Coolant Level
2. Oil Pressure to low
3. 5 lbs at Idle,.40 to 50 lbs. @ 1800 RPM
4. Crank Case Back Pressure, from worn out Piston Rings,or Liners.
5. There is a Oil Pick-Up Strainer inside the Oil Pan, but usually does not need changing.
6. 170 to 195 Degrees Loaded and underway.
7. Usually Governed at 2250 RPM, no Load on engine, but underway/loaded, 1500 to 1800RPM
8. Governor normally maxes 2250 RPM.
9. 15000 to 18000 Hours
10.Only if the Gasket is damaged upon removal..it's normally rubber, so should be okay. |
johnoxley
Senior Member
Username: johnoxley
Post Number: 146
Registered: 04-2010
| | Posted on Tuesday, October 20, 2015 - 08:30 am: |
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Spoke to our GM guys, who supplied same figures as above. As well, the 6-71s in our tugs don't like cruising at low to moderate speeds. Our skippers were running at gentle speeds to towing jobs - Then when the towing work commenced --> OMG at the smoke! Problem went away when skippers pushed the engines on the way to tows. We were also advised by GM mechanics not to treat GMs gently and also to switch off and restart later instead of idling for long periods. |
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