starving for fuel? starter dead!

[boattoy]

Alright... who dumped the water in my gas tank? . Today my boat (86 470) finally ran awesome untill just before i was ready to go in. It starts to starve for fuel if you run it above 3k or so. What happens is i get the boat on plane and it runs fine for about 10-15 sec then it falls on its face back down to idle. It doesnt actually die if i let off the throttle. it will go back to idle. if i idle it for a little bit i can get up on plane and it runs awesome all the way to WOT for another 10-15 secs. it will idle and run below 1500 all day long.

so far i pulled the hose going from fuel seperator to pump and hook up a manual bulb pump and its pulling fuel out of the tank and through that filter fine. i just had the pump off a few weeks ago(diaphragm seems to be fine,strong sucking when i would actuate the pump by hand) because i thought it was bad but it turned out to be the tank pickup. I did NOT replace the filter in the pump since i didnt have another one. It looked alright, just really old but not plugged(bought new one today though). I DID replace filter at the carb though.

My guess is its the needle/seat/float. i dont have gas smell in oil and no gas is coming out of the yellow tube. i have a spare carb thats either brand new or rebuilt(dont recall) im willing to swap out if you guys think its a carb issue and not the pump. all opinion welcome. I was told by local marina that pumps can get weak and not blow.

Im 99% sure its not timing related. I got a brand new coil and pertronix 2 module that i just installed. Boat fires right up.


see post 9 for starter issue. thanks!

 

[boattoy]

Re: starving for fuel?

Re: starving for fuel?

I got the pump filter off and half of it got crushed. Also I was able to easily pull one of the ends of the filter off.

Now im curious. it says to install filter with open end facing DOWN(fuel bowl faces down). If i put it in that way it doesnt fit good at all and i dont know how it would even work. This is a mercruiser manual(factory one).

 

[Volphin]

Re: starving for fuel?

Re: starving for fuel?

Ditch that old thing and install an electric pump. There's a reason why they don't get spec'ed much anymore.

V

 

[Volphin]

Re: starving for fuel?

Re: starving for fuel?

BTW, have you confirmed that the new ign parts are operating properly?

V

 

[Beefer]

Re: starving for fuel?

Re: starving for fuel?

Along with replacing the FWS, with that old of a boat (mine is an '84), your fuel lines could be deteriorating from ethanol (let's not turn this into an ethanol thread). As I learned here, when it's a fuel issue, you have to determine if it's a boat-side or tank-side problem. Get a remote fuel tank (6 gal Moeller works great), and hook up to it. See if the problem still exists. If it does, it's a boat-side problem, if not, it's a tank-side problem.

Boat-side problems could be carb, fuel pump, fuel pump diaphragm, deteriorated fuel lines (I would take off an older looking fuel line and cut it open, and see what shape it's in), or filters. Start with the filters, then the lines. You can tell if the fuel pump/diaphragm is ok if there is no fuel going through that (clear-ish) tube that goes from the pump up to the carb. If there is fuel in it, your diaphragm is shot (you've already covered this). Check your vacuum on the fuel pump. Then go to the carbs. Those are the most common causes for a fuel starvation problem boat-side. There are others, but those will keep you busy.

If it's tank-side, check for water in your fuel, crud in your tank (golden brown sand-like particles or flakes), check the ball check valve (replace or eliminate as necessary), and the screen inside the fuel pick-up tube inside the tank. The screen inside the pick-up was my problem last year. (You have to separate the tube to get to it.)

Upgrading to a new electric pump is nice, but my be unnecessary.

As for the FWS filter install, the bowl has to be down. Otherwise, you can't drain it.

Good luck.

 

[Beefer]

Re: starving for fuel?

Re: starving for fuel?

Although I doubt this would be applicable, but I'll add it for others; make sure the fuel tank vent is unobstructed, and functioning fine.

 

[boattoy]

Re: starving for fuel?

Re: starving for fuel?

Fuel lines are new...vent seems fine.here is a pic of filter

 

[Beefer]

Re: starving for fuel?

Re: starving for fuel?

Fuel lines are new...vent seems fine.here is a pic of filter

Have you replaced that filter yet, and ran it? If you have, then I'd start with the easiest stuff first (other filters/screens), then move into the carbs. Was the boat sitting for a long time (1 or more years)? Have you tried to de-carb the carb? Is everything else running correctly (timing, etc.)? You could try and do the Seafoam carb cleaning, see if that does anything.

 

[boattoy]

Re: starving for fuel?

Re: starving for fuel?

took it out again today and ran it all day problem free until we were heading back in. it started doing it but not as often. i could run it for a few mins. Im thinking fuel pump is just breaking down and not liking the high rpm. Iam getting what looks like condensation out of the yellow tube going to carb, ( not raw gas)

Now that i got that pretty much figured out i got another problem. My "reman" starter took a dump on me. It clicks then buzzes. thought motor was vapor locked, towed in. Crank turned over fine with a breaker bar. Went to bump starter and it kinda cranks for a sec and makes some weird noises. i cant catch a break. funny thing is the motor itself that's supposed to have all these issues is the only thing that hasnt giving me trouble.

 

[boattoy]

Re: starving for fuel?

Re: starving for fuel?

well... even after a new pump its still doing it. as of right now Ive replaced:

fuel pump
fuel filter separator.
fuel filter going into carb
fuel lines
fuel tank pickup

It ran great all day again. towards the end of the day it started cutting out. If it sits for 30sec to 1 min it will crank over and run at 1500 or less rpm for 1min to 5 min. right when it died i pulled the spark arrestor off and i could see two good streams of fuel pumping down the carb when you pump the accelerator. My guess is something is plugging up a jet. Weird how twice now it will run for hours without missing a beat and then start dieing. Both times gas gauge only got to about half. when i fill it back up its never more then 10 gallons(18 gallon tank).