Well, this is the situation - I'm new to all this and this is the first time I'v bled my diesel. I changed the old filter from a
Fram to a Racor. Replaced the main filter and cleaned the screen. I opened the bleed screw and pumped fuel until it flowed with no bubbles. Started the engine and it ran for about 10-15 minutes, sped up a little and died. I hadn't bled the high pressure system. I bled the first vent at the CAV fuel injection pump and tried to bleed the second. It was hard to tell if it was right. The manual said to open the throttle all the way and crank until bubble free fuel resulted. I then tried the injectors. The rear injector seems to spit a fuel mist but not the forward one. By now the engine has been cranked for about 2-3 minutes off and on. I plan on going bact to the beginning, as I suspect a bubble somewhere BUT - I have in the back of my mind that I read or heard that too much cranking of the engine without the boat turning over could result in water buildup in the muffler which could then siphon back into the engine. Any idea if this is right? If so, how do I get rid of the water in the muffletr to try again? I can hand turn the engine with the compression relief on (off?). Will this work to get fuel through the High pressure system? Will it also cause the water buildup problem? Do you remember when you were a rookie? Any insight, help, encouragement, would be greatly appreciated. Thanks guys (and gals).
John
S/V Mariah
Cape Dory Intrepid 9M
john_dupras@hotmail.com
Help bleeding Volvo MD7A
Moderator: Jim Walsh
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Mark Yashinsky
Re: Help bleeding Volvo MD7A
First, YES, much cranking of the engine w/o disconnecting the water injection hose WILL fill teh muffler back to the engine w/ water. This can be bad as water can get into the engine (exhaust valves) and stop the engine from turning (hydro locked, water is non compressable) and possiblem damage something. Remove the hose from teh engine that injects the "used" seawater cooling water into the exhaust loop and just let it run into the bilge. Leave it there until you get the engine running, THEN RECONNECT IT IMMEDIATELY!! Next, look for a drain plug under the muffler to get the water out of the exhaust. Now comes the fun part....
Bleeding the fuel system. First, do you have a manual pump on the Racor filter??? I assume this the the first filter (and water seperator) and there is probably a smaller one onthe engine before the fuel goes into the engine. If you have a pump onthe Racor, great. You have to get pressure up in teh system and then in order as the fuel flows, open the bleed screws and/or pipe fittings so that only fuel flows (no bubbles). Be careful of having a bleed point open when you are draw stroke of the manual pump, you can draw air back in. The order should be something like this, the output of the Racor, the input then output ofthe engine fuel filter (if applicable), the input to the injection pump (probably a bleed screw), then the fitting at the top of the injectors. If you get past the pump clear of air, the rest (the injectors) should clear once the engine starts cranking. Make sure all that you loosen up is tight again (careful not to over do it!!) then try starting her up. If she starts, get the water injection hose back on the exhaust loop (might be HOT). Run her for a slightly elevated idle (1200RPM) for a number of minutes and look for any leaks. Try it.
Bleeding the fuel system. First, do you have a manual pump on the Racor filter??? I assume this the the first filter (and water seperator) and there is probably a smaller one onthe engine before the fuel goes into the engine. If you have a pump onthe Racor, great. You have to get pressure up in teh system and then in order as the fuel flows, open the bleed screws and/or pipe fittings so that only fuel flows (no bubbles). Be careful of having a bleed point open when you are draw stroke of the manual pump, you can draw air back in. The order should be something like this, the output of the Racor, the input then output ofthe engine fuel filter (if applicable), the input to the injection pump (probably a bleed screw), then the fitting at the top of the injectors. If you get past the pump clear of air, the rest (the injectors) should clear once the engine starts cranking. Make sure all that you loosen up is tight again (careful not to over do it!!) then try starting her up. If she starts, get the water injection hose back on the exhaust loop (might be HOT). Run her for a slightly elevated idle (1200RPM) for a number of minutes and look for any leaks. Try it.
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Larry DeMers
Re: Help bleeding Volvo MD7A
John,
The characteristic that you described, as the engine quit..running slightly faster, then quitting -is something that I also have seen. It is fuel starvation, due to air embolism. (as you probably guessed).
I suggest that bleeding the engine be always done the same way. Start on the low pressure side..at the lift pump. You have already cleaned the screen/filter there, so next loosen the air bleed screw on top of the primary filter on the engine..the larger cannister filter, that screws into the cap. The screw you want is at the top of the cap. Loosen it slightly..3-5 turns, and slowly push down the lift pump lever. The stroke should have about 3/4 in. travel to it (if not, *hand* rotate the engine 1/4 turn and try again). At the bottom of the travel, close the bleed screw down, and release the lift pump handle. Repeat, until there is pure fuel coming out of the bleed screw on each pump stroke.
Next, I go to the high pressure side at the injector nuts. Put a wad of paper toweling around the injector and then turn the engine over with the decompression lever lifted, and the muffler plug pulled out to allow pumped water to drain from the muffler body.
Pump until the flow is clear of air. Repeat with the second injector.
Reconnect everything, and then restart and check for leaks at the injectors.
If you continue to get air into the high pressure side, there is a fault in the high pressure line/coupling somewhere. This injector pump is a self-bleeding pump, so it should get rid of any small amounts of air trapped inside..sending the air back to the tank.
The other possibility is the tiny little ball check valve for each high pressure line (or maybe there is only one for both). This little spring loaded valve will crud up incredibly easily. If it hangs up in the open position, it will allow air to infiltrate the high pressure lines while the engine sits between uses.
Good Luck,
Larry DeMers
s/v DeLaMer
Cape Dory 30
demers@sgi.com
The characteristic that you described, as the engine quit..running slightly faster, then quitting -is something that I also have seen. It is fuel starvation, due to air embolism. (as you probably guessed).
I suggest that bleeding the engine be always done the same way. Start on the low pressure side..at the lift pump. You have already cleaned the screen/filter there, so next loosen the air bleed screw on top of the primary filter on the engine..the larger cannister filter, that screws into the cap. The screw you want is at the top of the cap. Loosen it slightly..3-5 turns, and slowly push down the lift pump lever. The stroke should have about 3/4 in. travel to it (if not, *hand* rotate the engine 1/4 turn and try again). At the bottom of the travel, close the bleed screw down, and release the lift pump handle. Repeat, until there is pure fuel coming out of the bleed screw on each pump stroke.
Next, I go to the high pressure side at the injector nuts. Put a wad of paper toweling around the injector and then turn the engine over with the decompression lever lifted, and the muffler plug pulled out to allow pumped water to drain from the muffler body.
Pump until the flow is clear of air. Repeat with the second injector.
Reconnect everything, and then restart and check for leaks at the injectors.
If you continue to get air into the high pressure side, there is a fault in the high pressure line/coupling somewhere. This injector pump is a self-bleeding pump, so it should get rid of any small amounts of air trapped inside..sending the air back to the tank.
The other possibility is the tiny little ball check valve for each high pressure line (or maybe there is only one for both). This little spring loaded valve will crud up incredibly easily. If it hangs up in the open position, it will allow air to infiltrate the high pressure lines while the engine sits between uses.
Good Luck,
Larry DeMers
s/v DeLaMer
Cape Dory 30
John D wrote: Well, this is the situation - I'm new to all this and this is the first time I'v bled my diesel. I changed the old filter from a
Fram to a Racor. Replaced the main filter and cleaned the screen. I opened the bleed screw and pumped fuel until it flowed with no bubbles. Started the engine and it ran for about 10-15 minutes, sped up a little and died. I hadn't bled the high pressure system. I bled the first vent at the CAV fuel injection pump and tried to bleed the second. It was hard to tell if it was right. The manual said to open the throttle all the way and crank until bubble free fuel resulted. I then tried the injectors. The rear injector seems to spit a fuel mist but not the forward one. By now the engine has been cranked for about 2-3 minutes off and on. I plan on going bact to the beginning, as I suspect a bubble somewhere BUT - I have in the back of my mind that I read or heard that too much cranking of the engine without the boat turning over could result in water buildup in the muffler which could then siphon back into the engine. Any idea if this is right? If so, how do I get rid of the water in the muffletr to try again? I can hand turn the engine with the compression relief on (off?). Will this work to get fuel through the High pressure system? Will it also cause the water buildup problem? Do you remember when you were a rookie? Any insight, help, encouragement, would be greatly appreciated. Thanks guys (and gals).
John
S/V Mariah
Cape Dory Intrepid 9M
demers@sgi.com
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John D
Re: Help bleeding Volvo MD7A
Thanks Mark - I see where I may have made a couple errors. I have no pump on the Racor, but I don't believe I held the feed lever down and tightened the screw each stroke. As I understand your post, I should be able to bleed through to the High pressure pump using the hadn pump and then crank it to push the last of the air through the injectors and Voila!!. I'll give this atry this weekend and hope for the best. At least I'm learning a lot.
Thanks.
John
S/V Mariah
john_dupras@hotmail.com
Thanks.
John
S/V Mariah
john_dupras@hotmail.com
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John D
Re: Help bleeding Volvo MD7A
Thanks Larry - The only difference I can see from your instructions and the manual have to do with the High Pressure pump. Mine is a CAV type and has 2 bleed screws on it. I will pull the muffler plug and give it a try from the beginning. The other thing I didn't do was close the bleed screws while holding down the pump lever. (In fact, when I first started pumping the lever, I didn't realize that the first resistance I felt on the down stroke was really the beginning of the pumping action and pumped the damn thing about 1000 times with no results. Live and learn.) I will try again this weekend and let you know how it turns out. Thanks
John
S/V Mariah
john_dupras@hotmail.com
John
S/V Mariah
john_dupras@hotmail.com
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John R.
Re: Help bleeding Volvo MD7A
The recommended bleed procedure by Volvo for the MD7A (MD6A also) based on Volvo publication #3023 and addendum is as follows:John D wrote: Well, this is the situation - I'm new to all this and this is the first time I'v bled my diesel. I changed the old filter from a
Fram to a Racor. Replaced the main filter and cleaned the screen. I opened the bleed screw and pumped fuel until it flowed with no bubbles. Started the engine and it ran for about 10-15 minutes, sped up a little and died. I hadn't bled the high pressure system. I bled the first vent at the CAV fuel injection pump and tried to bleed the second. It was hard to tell if it was right. The manual said to open the throttle all the way and crank until bubble free fuel resulted. I then tried the injectors. The rear injector seems to spit a fuel mist but not the forward one. By now the engine has been cranked for about 2-3 minutes off and on. I plan on going bact to the beginning, as I suspect a bubble somewhere BUT - I have in the back of my mind that I read or heard that too much cranking of the engine without the boat turning over could result in water buildup in the muffler which could then siphon back into the engine. Any idea if this is right? If so, how do I get rid of the water in the muffletr to try again? I can hand turn the engine with the compression relief on (off?). Will this work to get fuel through the High pressure system? Will it also cause the water buildup problem? Do you remember when you were a rookie? Any insight, help, encouragement, would be greatly appreciated. Thanks guys (and gals).
John
S/V Mariah
Cape Dory Intrepid 9M
Open the bleeder screw on the fine filter. Pump fuel until about 0.2 litre (0.2 qt.)of fuel has run out. Close bleeder screw. If pumping effect is poor, turn engine over a bit so the pump drive cam alters its position.
Only when the injection pump has been removed or when starting a new engine for the first time, should the injection pump be bled. In such a case pump with the primer pump for 1/2 minute. This automatically bleeds the injection pump. Slacken the delivery pipe nuts on the injectors and turn over the engine until fuel comes from the delivery pipes. Tighten delivery pipe nuts and start the engine.
Here is the way I do mine and never have any problems:
I have a Racor 220 with the primer pump. I first pressurize the system up to the engine primer pump using the Racor pump. I open the bleed screw slightly on top of the engine filter. I continually pump the engine primer lever until a steady stream of fuel without visible air flows from the screw then shut it promptly. Next I go to the banjo fitting nuts on the injectors and continue the bleeding procedure using the engine primer pump. It is quicker and easier to turn the engine over in lieu of using the pump but then you are faced with the water/exhaust issue unless you close the seacock.
My method of using the primer pump allows one person to do the job alone and without excess water build up worries. Bleed one injector banjo fitting ( Volvo calls them the delivery pipe nuts) at a time. Do not over tighten the banjo nut as you can easily shear them off, they are hollow and break easily. Also be very careful not to distort the banjo fitting washers, snug is plenty tight. There are two of them on each banjo fitting. If you have a persistent air leak replace those washers and the washer on the filter bleed screw.
The importance of the excellent condition of those washers can't be overstated. The washers are dirt cheap and yet I've seen them as the root of a lot of air leakage problems on diesels. Once you have properly bled the filter and injectors the engine should start and run fine. As Volvo states, don't mess with the injection pump, totally unnecessary.
A ten minute run and then stalling almost tells me you have an algae problem, but then it could be small amounts of trapped air as well. There are a few things you can eliminate as possible air leak causes:
Double check all fuel line connections, do not over tighten any hose clamps as they can put small cuts into the hose and permit air to enter. Be sure your Racor components are sealed properly (o-rings and filter washer), check your engine filter seal as well.
If the problem persists, rebleed and try again. If that fails and you are reasonably sure you pumped out all air then I would be looking at the banjo washers as a possible culprit.
Are you absolutely sure air is the problem and you don't have an algae problem? Put a flashlight up to the bowl on your Racor and look very closely for black sediment in the bottom of the bowl. If you discover an algae problem post another message and we will walk you through that dilemma.
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Scott Ritchey
Re: Help bleeding Volvo MD7A
John
If you don't have a primer pump on the new filter (you can but it with or without) you may want to splice a hand squeeze bulb between the tank and the filter. West and others cary them .. just get one with the right size fitting to slide over your hose. The regular engine-mounted pump may do the job (by sucking fuel into the filter) but the bulb seems faster.
Don't recall if you did this, but you can also pre-fill the filter with fuel before you install it to reduce the required amount of priming.
Also I have operator and shop manuals for the MD6/7 that are surplus if you need/want them. My previous boat (a Columbia lost in hurricane Opal) had a MD-7. Boat is gone, but I still have the manuals.
Ritcheyvs@aol.com
If you don't have a primer pump on the new filter (you can but it with or without) you may want to splice a hand squeeze bulb between the tank and the filter. West and others cary them .. just get one with the right size fitting to slide over your hose. The regular engine-mounted pump may do the job (by sucking fuel into the filter) but the bulb seems faster.
Don't recall if you did this, but you can also pre-fill the filter with fuel before you install it to reduce the required amount of priming.
Also I have operator and shop manuals for the MD6/7 that are surplus if you need/want them. My previous boat (a Columbia lost in hurricane Opal) had a MD-7. Boat is gone, but I still have the manuals.
Ritcheyvs@aol.com
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mark Yashinsky
Re: Help bleeding Volvo MD7A
Then you probably have a manual on the engine (mechanical) fuel pump. Again, on the pressure side (towards the engine), find the first vents, pump till clear of bubbles, tighten then go to the next. you want teh injector pump clear of air (some can pump air and self prime, most, however, cannot). Once the injector pump is clear of air, it can pump fuel and clear the rest (the injectors). Since you said it ran then died, check all the fitting before the mechanical lift pump (not the injector pump). You might have something loose and drew in air. Particulary the Racor if it is between the lift pump and fuel tank. This area is under vacuum drawing fuel from the fuel tank.
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John D
Re: Help bleeding Volvo MD7A
John - I'm pretty sure it's not an algae problem as it has been running fine. I run it a half hour or so once a week. I replaced an old Fram filter that I couldnt see through with the new Racor. I'm pretty sure I just haven't bled it quite right as it's my first try at this. Thanks for the info and I'll let you know when Mariah runs again.
John
john_dupras@hotmail.com
John
john_dupras@hotmail.com
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John D
Re: Help bleeding Volvo MD7A
Scott - I'd love to have the manuals. Shoot me an e-mail with how much you want for them and I'll get you my adress. Thanks!
John
john_dupras@hotmail.com
John
john_dupras@hotmail.com
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John R.
More
One half hour or so of running time does not disqualify you from having an algae problem. The algae just has to collect to a high enough quantity to cause misfires or total stalls like you are dealing with. I would shock the tank with BioBor just to be on the safe side, run engine if possible and then change primary Racor filter after it begins to build with dead algae.John D wrote: John - I'm pretty sure it's not an algae problem as it has been running fine. I run it a half hour or so once a week. I replaced an old Fram filter that I couldnt see through with the new Racor. I'm pretty sure I just haven't bled it quite right as it's my first try at this. Thanks for the info and I'll let you know when Mariah runs again.
John
Have you checked for water in your tank or in your Racor collection bowl? It will take awhile to collect in the Racor bowl that's why you should check the tank with test strips. Try using some test strips and see what they indicate. You sure don't want any water getting into the injection pump! I'm sure there is water, usually is in any vented tank of any decent capacity size. Does your tank have a fine screen on the tank pick up tube? It could be blocked or partially blocked. I removed mine long ago. Check your tank vent line to make sure it is unobstructed.
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Richard Feffer
Re: Help bleeding Volvo MD7A
John,
I don't believe you have an algae problem either. I had a problem EXACTLY like yours a few years ago with my Yanmar. The problem turned out to be the Raycor filter. I spent considerable time on the phone with Raycor rep. After replacing filter with a new one, the problem dissapeared. I'm not sure if it was a defective filter or the fact that I didn't lubricate the seals prior to installation. Make sure you put some grease on the inner rubber seal and the gasket.
Good luck.
Richard
RichFef@Prodigy.net
I don't believe you have an algae problem either. I had a problem EXACTLY like yours a few years ago with my Yanmar. The problem turned out to be the Raycor filter. I spent considerable time on the phone with Raycor rep. After replacing filter with a new one, the problem dissapeared. I'm not sure if it was a defective filter or the fact that I didn't lubricate the seals prior to installation. Make sure you put some grease on the inner rubber seal and the gasket.
Good luck.
Richard
RichFef@Prodigy.net