no start Yanmar

[rchad]

I've been experiencing great frustration trying to get my Yanmar 2GM started for the past few weeks.

Just before Hurricane Irene last August, after some significant rain, I discovered that my fuel tank was covered with water. I pumped the bilge and checked the primary filter for water in the fuel. Finding none, I started it up. The engine started fine and I still noticed no water in the primary filter. I did remove the top cover of the primary filter as I motored up the river to Liberty Marina because I was worried about the possibility of water getting into the engine. Then I feared that I may have introduced air into the fuel line

The motor ran fine for about an hour, but after shutting down, it was hard to start. When it did start I noticed black smoke in the exhaust and the prop complained when I put the boat in gear.. I shut it down and ended up pulling the boat for the season. I've been unable to start it since.

I have bled the system up to the fuel injectors, but still no luck. The engine cranks, seems to fire, but wont run on its own. I've charged the four year old batteries and had them tested. They seem to test OK.

Any ideas as to what to check next?

[HPLou]

There is a good chance that there still is some air in the line. I would first try to bleed the system again. The black smoke could be the engine was firing on one cylinder.

[centaursailor]

Check that the seal on the primary filter seated properly when you retightened,
also double check all joints you opened. Looks like air is getting into the system.

[jrd22]

On the 3GM I had (not sure if the 2GM is the same), there was a bleed screw on the top of the secondary fuel filter housing. Using the hand pump if I got good fuel flow there the engine would start and only occasionally need bleeding at the injectors. I agree that you should check the seal on the primary filter. I trust you know about keeping the seacock closed for the cooling water while cranking?

[rchad]

How will I know if I've found any air in the fuel system? i've bled the system numerous times at the secondary fuel filter, injection pump and at both cylinders. I'm getting no bubbles in the first two locations seeing squirting fuel at the cylinders. How stubborn could this air in the system be to find?

[Gary M]

You could have an ongoing air leak, check all of your connections. Got stranded on a delivery once because of an air leak at a fitting.

[dabnis]

One way to find an air leak is to pressurize the whole system like this:
The Diesel Page, Electric Lift Pump and Racor Filter installation
Pump can be mounted right after the tank outlet for testing. I believe some have a "flow through" feature that allows the electric pump to be left in place and used only for bleeding or emergencies if the regular pump fails. If the regular pump's diaphram fails fuel could possibly leak through into the crankcase? If using the electric pump on an ongoing basis it might be a good idea to by-pass the diaphram pump?

Dabnis

[beachmont]

If you can start with quick start it's air/ fuel I got air on mine draining the fuel filter Cracked injector line bleed air out that way If you google check out owners man. It will tell what to do

[rchad]

I seem to be getting fuel to the injectors, because when I bleed the line at the injection point, it squirts out. Is it possible that a clogged injector could be causing fuel to not get to the cylinder and make the engine fire up?

[arf145]

The rule of "last thing messed with caused the problem" suggests that your primary filter did not seal properly and is letting air in. What kind of primary filter is it? If there's an O ring or gasket involved in the part you opened up, I'd replace that.