Close raw water valve when hard starting??

[AaronJ]

Hi, I have a Yanmar 2GM20F that required several cranks before starting. I did the basic maintenance recently...new filters, impeller, injectors serviced, pulled head and cleaned valves and cylinder. I'm anticipating a lot of cranking as I bleed the fuel system, so should I close the raw water intake valve, so I don't flood the engine? Then, open it when engine starts. I do have an anti-syphon valve on exhaust side.

Thanks,
Aaron

 

[Captn Dare]

hand pump

Aaron,
If you think you're going to be cranking the engine for a bit it's probably best to shut off the intake seacock until it starts just to be safe. Not great for the impeller but safer. A hydro locked engine is a bad thing and in this case and anti siphon valve won't make any difference. Better bet is to use the lever on the fuel feed pump to bleed the engine. If you can get clear fuel out the bleed screw on the secondary filter and at the injection pump it should fire after only a few cranks.

 

[kloudie1]

If ya gonna crank it without runnning, definitely close the seawater intake valve.. To prevent suction damage to the impeller, it is best to remove the suction side water hose on the water pump as well.. There will be enough residual water to keep it lubricated at low crank speed.. As Cap tn says, you can use the manual lever to bleed. If it doesn't feel like it is working you may have to hand rotate the engine a half turn or so to get the pump off the cam lobe and allow the lever to work. If the pump is belt driven, you could simply loosen the belt so the pump doesn't turn..

 

[m&d]

I never have a lot of patience for using the mechanical lift pump on the side of the engine. Before I crank my 2GM20F I use a short length of tubing at all the bleed screws the draw fuel through the system to the high pressure pump. At least you don't have to purge the filter bowl by cranking.
A buddy has a neat system. He has made an adapter to fit the fuel filler neck, blocks off the tank vent, then applies a little positive pressure to the tank with a bicycle pump. Then he works his way through the system cracking all the fittings open (one at a time) til he purges all the air out to the cylinder head. I've never seen it, but it sounds good...

 

[Steve Dion]

I agree that you should close the raw water intake. My question would be, is this engine always hard to start?

 

[Warren Milberg]

Not sure what type/kind of fuel filters you have on your engine, but on my 2GM20F I hardly ever have to bleed the system after changing the primary and secondary filters. I just fill up the filters as full as possible with diesel, try to get them screwed back in place without dripping too much fuel, and then hit start. Once in a while, I do bleed the system at the secondary filter, but I avoid having to pump the lift pump lever much as both filters are just about full of fuel anyway.

 

[AaronJ]

Thanks for all the replies. The popular vote is to close the intake seacock. This engine has taken about 5 - 10 crankings to start. I've owned it for 2 years and the previous owner had the same problem, so I replaced all the filters, impeller, cleaned the heat exchanger, serviced injectors, pulled head and cleaned it (it might be time for a valve job). I also pulled the entire electrical system, cleaned the connections, removed dead batteries, and rewired properly. It's almost time to start her up, so we'll see what happens. I would love to get a cheap compression tester, but it seems like $100 plus $150 for the Yanmar adaptar.

 

[bigsick]

What is hard starting?

Just bought my 2003 Hunter with a 2GM20F engine. Boat was not in water for 2 years before I dropped it late this summer for 2 months of sailing. Engine seems to run fine, but is rough sometimes. What should I do in spring to tune up engine. I am sure engine has never had service since it only has 50 hours. What is hard starting?

 

[Warren Milberg]

I think a diesel that needs 5-10 cranks to start has a problem you may not have yet discovered. Assuming your batteries and electrical system are delivering the needed cranking amps, and considering all the work you've done on the engine and electrical system, my guess is that your engine is not developing the needed compression to start faster. If the weather is not too cold, your engine should start the first time you hit the button, as my 23 yr old 2GM20F does.

 

[Captn Dare]

compression

Unfortunately, as Warren mentioned hard starting is often a compression problem. There are of course the usual suspects...head gasket, valves, rings...but what often gets overlooked is checking the piston height at TDC. Should the engine ever have been hydo-locked at some point it is possible for the force of the starter and flywheel momentum to bend a connecting rod/rods. It will often be just enough to lower the piston in the bore a wee bit and reduce the compression slightly. This is enough to cause hard starts when cold. It's something to check next time you have the head off. You'll need to buy or borrow a special micrometer (any engine machine shop should have one).

 

[dennisp]

I have gone to an informal Yanmar one-day owner familiarization/training class given by Norton Yachts (Deltaville) for the past two year that I have owned my 306. They have recommended the following:
- Use normal engine starting when it is warm and the engine has been run within the last 48 hours: hull sea cock open; turn key; avoid prolonged cranking of the starter.
- Use cold or 48 hour plus engine starting: 1) shut hull sea water sea cock; 2) with stop cable fully engaged (stop cable pulled out); 3) turn key 10 seconds then stop for 5 seconds; 4) turn key 10 seconds then stop for 5 seconds; 5) then disengage stop cable (push the stop cable in) while turning the key to start; and 6) subsequently open hull sea water cock. (My notes: (1) watch out for the LONG step going down (with the steps pulled out!) AND (2) careful with opening the thru-hull with the engine operating.)

Maybe TMI, but then I asked Craig, “and I want to do this because…I maybe want to get oil to the engine parts on top before it cranks over?”
“No.” he replies, “With cranking over and no start, you open the forward engine head (from the mixer) with no exhaust to push out the water! Do THIS procedure to make sure you aren’t getting water back into the engine before it kicks over.”

Thus, I have put the following on a 3x5 card (with one of my wife’s plastic recipe covers) that says:

COLD ENGINE START PROCEDURE:
If cold or 48 hour plus with no engine operations, use this starting
Procedure. Engine Starting:
1) Shut hull sea water sea cock on front of engine.
2) With stop cable fully engaged (i.e., the stop cable pulled out),
3) turn key 10 seconds then stop for 5 seconds, then
4) turn key 10 seconds then stop for 5 seconds again.
5) Then disengage stop cable (push the stop cable in) while turning
the key to start; and
6) subsequently opening the hull sea water cock.
[Careful for the LONG step going down AND careful with opening the
thru-hull with the engine operating.]

I keep it in the navigation desk. Hope this helps.