fuel flow, always check the basics!

[pcrussell50]

this goes for anyone...

but my motor is a 1959 super seahorse 35hp, rds21b...

anyhooo...

had this thing for 10 months now, and it was my first boat, ever. i've been sooo thankful that the guy who sold it to me was honest and that it has continued to run well and reliably. i've been crowing about it with pride on these pages from time to time, in fact.

well, the last couple of times i went out before today, it would start and idle like a champ, but under full throttle, it would surge and bog, surge and bog. the first time, i had let the gas tank get a little low, so i chalked it up to that. but not the second time. and i had my mother and brother in it with me that time, and my brother, who bores easily was driving and wanting to go fast, [as fast as 3 people in a 35hp runabout can go, anyway], so he guns it and it's surging again. well damn! this time i'm in the back of the boat, [it's a 13 foot, two seater], and i think to squeeze the bulb. and damned if that doesn't bring it back to life each time.

so now i'm relieved it's not the engine's fuel system, [knock wood, because one day, it will be], and i'm thinking, oh well, buy a new bulb and new ends for the fuel line, and not really excited about spending the money with a nagging little fear that won't fix it.

so this morning, the wife and i are prepping it to head out for a little picnic on the ocean, before the afternoon breezes whip up a swell, and i notice that the tank i've been using, a common, red plastic 6-gallon deal, has a crack right above the fuel flow side of the fitting, and another right above the locking mechanism side of the fitting. well i'll be darned. that just had to be the problem. the crack was causing the fuel pump to suck air. so i switched to a different tank for our outing, and all was normal again.

i put some non-hardening sealer on the cracks, and will test it again when it cures a little.

lesson learned about checking the basics first before going crazy with anxiety over expensive repairs.

-peter

 

[tashasdaddy]

Re: fuel flow, always check the basics!

good to know.

 

[hartnetthere]

Re: fuel flow, always check the basics!

This is strange timing, but glad I read this post. Today I took my 15' flats boat w/1999 50hp Evinrude, out for a spin. Like yours, it surged, sputtered and then quit. I was puzzled so I checked the bulb (the boat has a built-in 20 gal tank) and it need some serious squeezing. Motor started right up and ran for about 1 minute. Same thing again. I limped back to the ramp.

The only thing I have done that may have caused this was to remove the fuel gauge sending unit because it wasn't working. I got it fixed and reinstalled it using the same gasket. Based on your cracked tanks finding, I believe (and hope) that my issue is the same and will be solved tomorrow when I again remove the sending unit and replace that gasket and add some sealer under it.

Sound like the place to start to anyone else?

 

[daselbee]

Re: fuel flow, always check the basics!

No, it won't help your problem.
You have to run your rig with a well vented tank, you can even run your rig with the tank filler cap off, and a bad gasket under the fuel tank sender is a smaller version of an example of just such a vent.
His cracking fittings were on the fuel pickup, causing air leaks into the fuel line.
Try squeezing the bulb when it starts to fail. If it picks up, look at the fuel pump.

 

[hartnetthere]

Re: fuel flow, always check the basics!

Ah, should have realized that myself. But thanks, instead I'll check the fuel pump. The manual says that there is a fuel filter built into the pump so that would be a good place to start. Thank you for the help and saving me wasting time at the wrong end of the fuel system.

 

[daselbee]

Re: fuel flow, always check the basics!

I don't see a filter built into the pump by examining the parts drawing. I see a filter in line just ahead of the pump mounted in a metal clamp bracket.

 

[hartnetthere]

Re: fuel flow, always check the basics!

The attached shows exploded fuel pump with instructions: "wash filter element B with clean solvent and a brush". The next page also shows an In-line fuel filter so I will look for both and let you know what I find.

 

[film495]

Re: fuel flow, always check the basics!

just to be sure - I've dumped 3 full 3 gallon tanks of gas out, just to rule out bad gas while troubleshooting. and I'm on my 3rd set of plugs - although, now I'm sure one tank of gas was bad and 1 set of plugs, would have taken infinity to solve and probably an expensive bill - to have a pro tell me I had bad gas one time and fouled up plugs another time, plus the time of bringing it in and waiting etc etc. the more time I spend around boats and motors, the happier I am I've learned some of the basics.