Engine problem - '85 Mercruiser 170

[spareparts]

just replaced fuel lines on a 2008 Intrepid 25 today. It needed it.

[scook]

Do I need to use USCG approved, below deck fuel line, either because it is required or because it is safer than automotive line? I haven't checked automotive pricing but the approved stuff is around $6/ foot at West Marine.

[spareparts]

For inboard in engines use A1 rated fuel line. The automotive line isn't approved and won't hold up as well as the marine hose. Look on line, you should be able to get a better price than that. I think I retail it for $3/ft. West marine has good prices on tackle and electronics, but they raape you on everythign else. Even with my Port Supply(comercial side of West Marine) I can beat their prices on engine stuff most anywhere else. Check with Jamestown Distributors or Ebasicpower.com

[THEFERMANATOR]

Automotive line also isn't meant to be used under vacuum, and will collapse. Learned this one the hard way. I paid $2.69 a foot for 3/8" marine fuel line from my local hose shop.

[scook]

You guys were right about West Marine prices. ebasic power had the hose for about half - next project, I'll plan ahead and buy smarter. I decided I wanted to get it done last weekend, so I went ahead and let WM thank advantage of me. Got my fishing buddy to help me fish in the new line, changed the fuel/water separator filter and plumbed through the transom to the kicker motor line. Got the line installed with no sharp bends anywhere. A little gas down the carb and it fired right up.

Hoping to sneak out early one morning this week to give it a good trial workout.

Funny thing (it's funny now that it's resolved) when I got it running, I looked down and the volt meter was pegged at zero - this is after just putting on an alternator kit recently. I kidded myself that it could just be the gauge but decided to test it. Not running, the battery voltage was good and running, the charging voltage was good, so it was the gauge. I whacked on the gauge for a while and it came up to a correct reading. Another project to do this winter.

[smokeonthewater]

Check the connections on the back of the gauge

[scook]

Will do - Thanks

[scook]

Changed the fuel lines - did a careful job - only gentle bends. When I cut the 10 year old hose open, was surprised to find it in good shape - slit it in half, bent it both ways back onto itself - no cracks, loose rubber or anything like that.

Still the same problem - started great & ran great for about 20 minutes and RPM started dropping off. Turned around and headed back - as it started coughing and wanting to die, I pumped the throttle and got a little more out of it. That tells me it must be a fuel problem - right?

I put some air pressure on the fill tube and got nice air flow out of the vent, so I don't see how it could be bad venting causing a vacuum to build up in the tank.

Oil doesn't smell of gas so fuel pump not leaking into crank case but I can't think of anything it could be at this point but the fuel pump???

Before I order a fuel pump, is there anything I'm missing? Remembering back 10 years when I got the boat because it was doing exactly the same thing, I replaced both the fuel lines and the pump before running it and distance, so it could have been the problem then.

Found this pump for a lot less than other prices I've seen - anyone know anything about this supplier or the product? http://www.cpperformance.com/p-23396...-861676a1.aspx It made me a little nervous that for this mechanical pump, the product description said it had solid state electronics and a simple 2-wire connection.

[THEFERMANATOR]

Originally Posted by scook

Changed the fuel lines - did a careful job - only gentle bends. When I cut the 10 year old hose open, was surprised to find it in good shape - slit it in half, bent it both ways back onto itself - no cracks, loose rubber or anything like that.

Still the same problem - started great & ran great for about 20 minutes and RPM started dropping off. Turned around and headed back - as it started coughing and wanting to die, I pumped the throttle and got a little more out of it. That tells me it must be a fuel problem - right?

I put some air pressure on the fill tube and got nice air flow out of the vent, so I don't see how it could be bad venting causing a vacuum to build up in the tank.

Oil doesn't smell of gas so fuel pump not leaking into crank case but I can't think of anything it could be at this point but the fuel pump???

Before I order a fuel pump, is there anything I'm missing? Remembering back 10 years when I got the boat because it was doing exactly the same thing, I replaced both the fuel lines and the pump before running it and distance, so it could have been the problem then.

Found this pump for a lot less than other prices I've seen - anyone know anything about this supplier or the product? http://www.cpperformance.com/p-23396...-861676a1.aspx It made me a little nervous that for this mechanical pump, the product description said it had solid state electronics and a simple 2-wire connection.

You sure thats the right pump? It says it's for a 3.0L not a 3.7L. ust looked it up and see nthe 2.5L, 3.0L, 3.7L, and I guess the straight 6 all used the same pump. I see IBOATS also has it for about the same price for a sierra, and ebasicpower has a GLM for $129.95.

[scook]

With people who say a mechanical pump has solid state electronics and, 2-wire connection, I'm not real sure of anything but the Mercruiser part number they start with is the correct one. For a few bucks more, I'll go with a known supplier.

You think I'm on the right track swapping out the fuel pump at this point? Anything I'm missing?