Well it finally happened. After going under a draw bridge I started losing RPM until the little motor finally quit. After tacking up a narrow channel I coasted into a marina under sail and went to work on the motor. An obstruction (crud) was blocking the fuel line from the tank. After clearing the obstruction and cleaning the filters I still cant get the engine to run. I try to bleed the system but the little finger pump does not appear to be doing anything. Is it possible that because of the obstruction in the line, I ruined the pump diaphram ? The engine is a 3gmf 20 horsepower. Any thoughts ?
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Replace your fuel hose.
Travis: Be careful, you said you had a 3gm20. You probably meant a 3gm30.... Anyway, I would suggest that you replace you fuel line too. This is a good time to do this. Then be sure that you have fuel in the filter. Sometimes the cam lobe is in the wrong position and the pump will not pump in this position. I would try turning the engine over and then try pumping again. You may want to be sure that there is NO blockage in the tank pickup tube (some compress air will work). Just work your way back to the secondary filter on the engine. Make sure that you do not have any air leaks (new hose should take care of that). You may need to bleed the injectors too (but that should be a last resort). If you cannot get it to work, call the Yanmar Mechanic and have them help you with the problem.
Travis: Be careful, you said you had a 3gm20. You probably meant a 3gm30.... Anyway, I would suggest that you replace you fuel line too. This is a good time to do this. Then be sure that you have fuel in the filter. Sometimes the cam lobe is in the wrong position and the pump will not pump in this position. I would try turning the engine over and then try pumping again. You may want to be sure that there is NO blockage in the tank pickup tube (some compress air will work). Just work your way back to the secondary filter on the engine. Make sure that you do not have any air leaks (new hose should take care of that). You may need to bleed the injectors too (but that should be a last resort). If you cannot get it to work, call the Yanmar Mechanic and have them help you with the problem.
Diaphram Failure
It is possible to ruin the fuel pump diaphram by requiring the pump to work against a strong suction. This can happen by running the engine when the fuel filter is crudded up even though it can still pass some fuel or by other blockages including crud. So "Yes" to your question, it is possible.
It is possible to ruin the fuel pump diaphram by requiring the pump to work against a strong suction. This can happen by running the engine when the fuel filter is crudded up even though it can still pass some fuel or by other blockages including crud. So "Yes" to your question, it is possible.
finger pump
Travis, I was never able to get that pump lever working (even after cranking the engine to reposition it in the rotation) until I learned the trick from the instructor at the Mack Boring Yanmar class a couple of months ago. Most of the motion on the pump handle is wasted. When you get to what seems like the end of the stroke, push it just a few degrees further. You'll feel the resistance. And in quiet surroundings, you can hear it work. Good luck.
Travis, I was never able to get that pump lever working (even after cranking the engine to reposition it in the rotation) until I learned the trick from the instructor at the Mack Boring Yanmar class a couple of months ago. Most of the motion on the pump handle is wasted. When you get to what seems like the end of the stroke, push it just a few degrees further. You'll feel the resistance. And in quiet surroundings, you can hear it work. Good luck.
Good scoop Bill
I've had a 3gm30f since 86 and even rebuilt it and didn't know that trick. What I did was first plumb in an electric fuel pump with valves to use it as a fuel transfer pump from the converted fresh water tank and also to prime the engine. That sucked! What I've settled on during our rebuild is one of those outboard engine primer bulbs. Just locate it in a convenient spot and pump it with the bleed open. You can also tell if you have an obstruction or blockage. But if you have crud in your fuel line, CLEAN THE ENTIRE SYSTEM! I also have a discussion of my fuel system changes to our H34 in our web site/page. Fred
I've had a 3gm30f since 86 and even rebuilt it and didn't know that trick. What I did was first plumb in an electric fuel pump with valves to use it as a fuel transfer pump from the converted fresh water tank and also to prime the engine. That sucked! What I've settled on during our rebuild is one of those outboard engine primer bulbs. Just locate it in a convenient spot and pump it with the bleed open. You can also tell if you have an obstruction or blockage. But if you have crud in your fuel line, CLEAN THE ENTIRE SYSTEM! I also have a discussion of my fuel system changes to our H34 in our web site/page. Fred
prime the engine through the first filter
Use a manual pump (like the ones used to change oil) to pull fuel out of the tank - this proves it isn't clogged - to the 1st fuel filter. Then fill that filter with fuel. Then the priming pump has a chance. You make have gunk other places in the system, the draw tube out of the tank for example. Once you are done, have a cleanning system come and clean your fuel... Well worth the cost. (In extreme cases, they have to dispose of your fuel)
Use a manual pump (like the ones used to change oil) to pull fuel out of the tank - this proves it isn't clogged - to the 1st fuel filter. Then fill that filter with fuel. Then the priming pump has a chance. You make have gunk other places in the system, the draw tube out of the tank for example. Once you are done, have a cleanning system come and clean your fuel... Well worth the cost. (In extreme cases, they have to dispose of your fuel)
Thanks Fred
Hey Fred, glad to share. I recommend the Mack Boring Class (actually it's put on by Engine City Technical Institute.) But I don't think they put on any classes West of Chicago. BTW I enjoyed your pictures when you posted them some weeks back. Do you have any more of the bilges with the cabin sole removed? I'd like to get a good view of what's under the sole of my H34 before I rip up the sole some future year (not too distant) for replacement.
Hey Fred, glad to share. I recommend the Mack Boring Class (actually it's put on by Engine City Technical Institute.) But I don't think they put on any classes West of Chicago. BTW I enjoyed your pictures when you posted them some weeks back. Do you have any more of the bilges with the cabin sole removed? I'd like to get a good view of what's under the sole of my H34 before I rip up the sole some future year (not too distant) for replacement.
Bill, I'll have a look
Just minutes ago I posted 5 new snaps that are up to date (Like tonight). They are on page two. I'll have to look for some old stuff. I can send it to you via email. Drop me a line at ss427@tscnet.com. My link is with this post. Take care. And Travis, good luck. Fred
Just minutes ago I posted 5 new snaps that are up to date (Like tonight). They are on page two. I'll have to look for some old stuff. I can send it to you via email. Drop me a line at ss427@tscnet.com. My link is with this post. Take care. And Travis, good luck. Fred
hand pump
Bill from Hilton Head is exactly correct. The pumping action is actually accomplished in the last bit of lever movement and you have to really push it down to the stop. In that last bit of downward push you will feel the resistance and it may take alot of pumping depending on the area of the fuel system you have been working on. It is surprising that so little makes the difference. I have bled my Yanmar 27 several times after changing both filters. It just takes patience and that little extra push! I do like to open up the area under the aft berth (provides ambient light around the Racor), then loosen the bleed screw just a tiny bit as I am using the hand pump. Then, as I pump I can see it gurgling (air escaping) as the lines/filter fill with fuel. E
Bill from Hilton Head is exactly correct. The pumping action is actually accomplished in the last bit of lever movement and you have to really push it down to the stop. In that last bit of downward push you will feel the resistance and it may take alot of pumping depending on the area of the fuel system you have been working on. It is surprising that so little makes the difference. I have bled my Yanmar 27 several times after changing both filters. It just takes patience and that little extra push! I do like to open up the area under the aft berth (provides ambient light around the Racor), then loosen the bleed screw just a tiny bit as I am using the hand pump. Then, as I pump I can see it gurgling (air escaping) as the lines/filter fill with fuel. E
Carry one of these.
I carry about two gallons of diesel in a Tempo tank stored in the sail locker. The outboard motor end of the hose is cut off. I remove the hose from the Racor filter and attach the tank hose. A couple squeezes of the bulb and she starts right up, no bleeding required. Now I have time to work on the problem. I did this after the second tow and before the unlimited towing insurance.
I test it each Spring, it is how I move from the lift to the slip after launch.
I carry about two gallons of diesel in a Tempo tank stored in the sail locker. The outboard motor end of the hose is cut off. I remove the hose from the Racor filter and attach the tank hose. A couple squeezes of the bulb and she starts right up, no bleeding required. Now I have time to work on the problem. I did this after the second tow and before the unlimited towing insurance.
I test it each Spring, it is how I move from the lift to the slip after launch.Got it going
Thanks for all of your help. We found an obstruction at the pick up tube in the tank. This in turn created a negative pressure in the supply line and sucked a gasked sideways in the pump. We replaced the gasket and bled the engine and she runs like a top. I am going to replace the fuel filters but I need some ideas on cleaning out the fuel tank. Are these fuel polishing guys any good ? Thanks again
Thanks for all of your help. We found an obstruction at the pick up tube in the tank. This in turn created a negative pressure in the supply line and sucked a gasked sideways in the pump. We replaced the gasket and bled the engine and she runs like a top. I am going to replace the fuel filters but I need some ideas on cleaning out the fuel tank. Are these fuel polishing guys any good ? Thanks again
Build your own.
Travis: Think about building your own fuel polishing system. You can get an electric fuel pump (diesel type) and some valves with an additional filter. You can just turn on the pump while you are at the dock and run all of your fuel through the system a couple of times per hour. I also like Bio-diesel to help clean up the sytem. You can use anywhere from 20% - 50% soy mixed with your existing fuel. This stuff does a very good job of cleaning your entire fuel system and also adds lubrication to your fuel too. You should also change out your fuel lines when if you decide to do any upgrades to your system. The same stuff that was in your tank is also living or dying in the rest of your fuel system. I'm glad to see that you get the engine runnign so quickly.
Travis: Think about building your own fuel polishing system. You can get an electric fuel pump (diesel type) and some valves with an additional filter. You can just turn on the pump while you are at the dock and run all of your fuel through the system a couple of times per hour. I also like Bio-diesel to help clean up the sytem. You can use anywhere from 20% - 50% soy mixed with your existing fuel. This stuff does a very good job of cleaning your entire fuel system and also adds lubrication to your fuel too. You should also change out your fuel lines when if you decide to do any upgrades to your system. The same stuff that was in your tank is also living or dying in the rest of your fuel system. I'm glad to see that you get the engine runnign so quickly.
You remind me of my obstruction (HAH!)
Let me tell you about my obstruction. That sounds gross. But after we were hit by lightening off the Panama/Costa Rica border, the alternator decided to need a rebuild at sea and all of that caused the engine to quit, not once but about a hundred times before we made the Panama Canal Zone. The fuel was bad because of a tropical down pour while fueling up at an anchorage outside of Puntaranace, Costa Rica with jerry cans. The engine would run but only for a short time. At first it seemed to be caused by the water that made it into the tank during fueling but the engine always started after bleeding. The bleeding was coincidental to the real problem. Because the engine died every minute and a half and always started with bleeding, we thought we were dealing with water in the fuel that was being purged when bleeding. After two days of this and a starter motor that was getting scary, I started to imagine a piece of plastic that came from the installation of the fuel pick up AT THE FACTORY. I imagined the piece of cutting now draped over the pickup and blocking the fuel but not coming off when the engine died. I imagined a plastic octopus/clapper valve. After two days of this (remember, we are in the doldrums, no wind) I disconnected the fuel line and blew into it. The result was just as a kid does with a soda straw. Lots of bubbles in the tank. Then I sucked on the hose. (gross again) You guessed it. NOTHING! Blocked solid or tight. I rigged a spare hose to a jerry can and sucked fuel into it with a hand pump. That worked and we almost made it to that island anchorage just off Balboa. (I can't recall the name) We didn't quite have enough good fuel. We towed the boat to a mooring with the dingy at night during another tropical down pour. The next day I broke out the saber saw and cut an inspection hole in the main fuel tank. I pumped out the contaminated fuel and looked inside. There it was! A plastic cutting from the fuel pickup installation that the factory didn't care about. After all this is just a production boat, right? (H34) I made repairs and even got free fuel from a tuna boat. I never took my fuel system for granted before that incident but afterward, I'm obsessive. Oh, check out my web site, I've been updating our rebuild and made a lot of changes over the last two days. Fred
Let me tell you about my obstruction. That sounds gross. But after we were hit by lightening off the Panama/Costa Rica border, the alternator decided to need a rebuild at sea and all of that caused the engine to quit, not once but about a hundred times before we made the Panama Canal Zone. The fuel was bad because of a tropical down pour while fueling up at an anchorage outside of Puntaranace, Costa Rica with jerry cans. The engine would run but only for a short time. At first it seemed to be caused by the water that made it into the tank during fueling but the engine always started after bleeding. The bleeding was coincidental to the real problem. Because the engine died every minute and a half and always started with bleeding, we thought we were dealing with water in the fuel that was being purged when bleeding. After two days of this and a starter motor that was getting scary, I started to imagine a piece of plastic that came from the installation of the fuel pick up AT THE FACTORY. I imagined the piece of cutting now draped over the pickup and blocking the fuel but not coming off when the engine died. I imagined a plastic octopus/clapper valve. After two days of this (remember, we are in the doldrums, no wind) I disconnected the fuel line and blew into it. The result was just as a kid does with a soda straw. Lots of bubbles in the tank. Then I sucked on the hose. (gross again) You guessed it. NOTHING! Blocked solid or tight. I rigged a spare hose to a jerry can and sucked fuel into it with a hand pump. That worked and we almost made it to that island anchorage just off Balboa. (I can't recall the name) We didn't quite have enough good fuel. We towed the boat to a mooring with the dingy at night during another tropical down pour. The next day I broke out the saber saw and cut an inspection hole in the main fuel tank. I pumped out the contaminated fuel and looked inside. There it was! A plastic cutting from the fuel pickup installation that the factory didn't care about. After all this is just a production boat, right? (H34) I made repairs and even got free fuel from a tuna boat. I never took my fuel system for granted before that incident but afterward, I'm obsessive. Oh, check out my web site, I've been updating our rebuild and made a lot of changes over the last two days. Fred
Engine bleeding
I gave up on the little thumb lever pump and installed an outboard motor fuel tank priming pump (squeeze type bulb) in the fuel line between the tank and ships fuel filter. It works extremely well. I can fill up a new, dry Raycor filter in just about three or four squeezes. With all of filters full of fuel, the lines bleed out in just a couple more squeezes.
I gave up on the little thumb lever pump and installed an outboard motor fuel tank priming pump (squeeze type bulb) in the fuel line between the tank and ships fuel filter. It works extremely well. I can fill up a new, dry Raycor filter in just about three or four squeezes. With all of filters full of fuel, the lines bleed out in just a couple more squeezes.
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