won't idle after fuel pump rebuild

[boatfan]

I just replaced most of the components of my fuel pump on merc 150 black max 2-stroke. The only reason I had to, was because the back gasket had lost seal and fuel was misting out. Everything looked good in the fuel pump so I only changed the both the diaphrams and the gaskets. After bolting back on, engine starts, runs for a minute or two and dies. I have to re-pump bulb and it fires right back up. I am quite sure the fuel pump went back together correctly and no leaks... anyone have any input??? :x

 

[Brent]

Does it have fuse?

 

[boatfan]

No, it doesn't that I know of, it doesn't seem to have any electrical components.

 

[Brent]

thanks for the update

 

[DaleH]

I'd bet that as it was going ... the carbs and sync/link were adjusted to account for the weakened pump. Now that the pump diapragm is new - it's out of whack, in relation to the rest of the OB setup. You need a tune up, sync & link 1st, then to tune/idle each of the carbs in sequence. After all 6 are adjusted, if you need to adjust 1, you need to go back over all 6 together in sequence, as they are inter-related.

I would not attempt this without the factory OEM service manual. But if you had one, they're easy to do yourself. Proper instruction and sequencing is the key here. Myself? I would not trust a Clymer or Seloc "1 size fits all" service manual.

 

[gw204]

I'm thinking the pump is pulling in air now that it's working correctly. If you have enough slack in the fuel lines, trim a little off the ends so you can slip fresh hose on to the barbs and resecure.

 

[DaleH]

I'm thinking the pump is pulling in air now that it's working correctly. If you have enough slack in the fuel lines, trim a little off the ends so you can slip fresh hose on to the barbs and resecure.

OMG, that's dangerous too, as the motor will run lean. Makes sense, runs lean = no fuel = shuts off. As is, the pump is driven by crankshaft revolutions, so it would want to pump anytime running, even if not running smooth.

Good call!

 

[boatfan]

thanks, someone else had mentioned that too, I am going to trim and re-secure the hoses tomorrow, I'll keep you all posted. I appreciate the input.

 

[DaleH]

thanks, someone else had mentioned that too, I am going to trim and re-secure the hoses tomorrow, I'll keep you all posted. I appreciate the input.

Don't use hose clamps, use the metal or plastic clamps DESIGNED for fuel lines that crimp/hold them in place without distorting the line.

That 'bunching' can happen with smaller hose clamps as it bunches up under the screw part, as the band only pulls & tightens from one end ...

 

[boatfan]

well no luck anyway, still kills after a minute or two. thinking of taking apart again and redoing the rebuild..

 

[boatfan]

nevermind, I had put the center block in flipped. She is running like a champ as I type this!!

 

[Brent]

good and didnt have any leftover parts

 

[boatfan]

I will actually save the diaphrams as they are in good shape, but no. Now all I left to do is fish the transducer cable from the transom to the console for my new Lowrance Elite combo..