Fuel flow problem

[remo7e]

My Yanmar YSM 12 just died on me last week. I have a Yamaha 30 and I admit it is a bit on the old side at 25. The fuel is just not moving.

The filters are fine and the fuel is clean as far as I can tell. I pulled the fuel pump off and could not find any holes in the diaphragm. When I use the toggle on the fuel pump, I get very little suction. Could this be just a bad fuel pump? Is there an easy way to tell if the fuel pump is bad?

Thanks in advance for any advice.

 

[Maine Sail]

My Yanmar YSM 12 just died on me last week. I have a Yamaha 30 and I admit it is a bit on the old side at 25. The fuel is just not moving.

The filters are fine and the fuel is clean as far as I can tell. I pulled the fuel pump off and could not find any holes in the diaphragm. When I use the toggle on the fuel pump, I get very little suction. Could this be just a bad fuel pump? Is there an easy way to tell if the fuel pump is bad?

Thanks in advance for any advice.

Hoses or the pick up tube in the tank may also be plugged..

 

[remo7e]

The pick up tube is the next thing on my list. I've had fuel flow problems twice now. Both times after the boat was rocking hard (stirring up fuel gunk?)

 

[kloudie1]

The toggle may be blocked by the cam that drives the fuel puimp.. Try turning the engine a half turn and see if the toggle works better. Ya may have to turn it another half turn to make the toggle fully free if it gets worse whern you turn it the first time. The cam turns at half engine speed so turning the crank a half turn, turns the cam a quarter turn. If you have someone there, have them SLOWLY turn the crank (fuel off and decompress on) while you repeatedly stroke the toggle until you can feel it working a full stroke.. Sounds like a fuel tank scrubbing is in order too.. Good luck with it.

 

[Paul F]

My 28 year old pump went last year. Replaced it with an electric fuel pump from an auto store. It works great and makes bleeding the lines very easy. I would not mess with the old pump the cost of a new electric pump is not much.

 

[remo7e]

My 28 year old pump went last year. Replaced it with an electric fuel pump from an auto store. It works great and makes bleeding the lines very easy. I would not mess with the old pump the cost of a new electric pump is not much.

I've heard of using an electric fuel pump. How do I determine the size of electric fuel pump needed? Do I just wire it into the nearest 12volt source?

I'm living in Japan, so it makes all this a bit more difficult.

 

[Paul F]

You do not need a large fuel pump. The one I put in was a generic Airtex #E8012S. Wired it to the ignition key so that it is only on when the key is on. The boat is a 1980, a new fused positive "red" wire was also run from the battery switch to the ignition key to ensure that the electric power was good.

 

[remo7e]

Thanks, I'll try this.

 

[remo7e]

You do not need a large fuel pump. The one I put in was a generic Airtex #E8012S. Wired it to the ignition key so that it is only on when the key is on. The boat is a 1980, a new fused positive "red" wire was also run from the battery switch to the ignition key to ensure that the electric power was good.

I just looked at the Airtex on Amazon. It doesn't mount? The picture wasn't that good, but it looks line you just put it in the fuel line. That might be better than the one I had looked at that needed to be mounted as there is limited space in the engine compartment.

 

[Paul F]

Fuel Pump

Yes, mine had a collar mounting like the one in the picture. The old pump was plugged and put back in the side of the engine. The fuel line was not run through the old pump. If I may suggest. Take the picture down to the local auto store and see if they have one in stock. Likely a better price and wait time than an internet shipment.

 

[Nereussailor]

Here's a couple of thoughts. I had the same problem on my Yanmar 2GM. I pulled the pump off and took it apart. Since the pump doesn't have any rebuild kit, and was going to cost around $80, I decided to look at it myself and see what I could do. Once apart, I determined that the diaphragm was still intact, and was not the culprit. I took out te two check valves that let the fuel flow in the proper directions. Under one was a small fiber washer it was not seated properly and well worn. I couldn't buy the part from any Yanmar dealer, so I went to Ace Hardware and found some tiny O-rings. I replaced the washer on the bottom of one chck valve, and one on the top of the other check valve. I put everything back together and submersed the pump completely in fuel. While immersed, plug up the fuel outlet with your finger and pump the rocker arm that rests on the cam and actuates the pump. If you see any bubbles coming out anywhere, you have a leak. Mine had a small leak coming out by the diaphragm. I took it apart again and checked the diaphragm and the pump housing for any imperfections. The diaphragm had a little area that looked like a buildup of gasket sealant or something. The housing had a slight pitting of the casting. in the same area. I took a small scraper and carefully scraped the gunk off the diaphragm. Then I sanded the casting carefully with some 600 grit wet sanding paper with a block backing it, making sure to use full even strokes across the whole casting, and taking off as little as possible. After cleaning everything, putting it all back together, and checking it again, I found that there were no leaks. The total cost of the repair was 43 cents. plus a little diesel fuel. I now have over 100 miles logged, and have had no problems as of yet. (Knock Wood)
I thought about replacing the pump with an electric one, but I learned from a question on the forum, that if my battery is dead, and I need to start my motor, I'm screwed with an electric pump. My motor is small enough to crank by hand if I had to. I might add an electric one as a secondary pump, but I don't like the idea of relying solely on an electric pump.

Dave