Fuel Issue Thoughts ?

[Outlawman]

Originally Posted by gecsr1

Can you switch the tanks to the engines, and see if the tank is the problem or if it's the carb engine. Actually change the inlet fuel lines to the engines .

Say what? Sorry but that's just not clear.
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[sickcat]

When you pull the filter that you have not touched yet open it up or at least dump it looking for water. Were both engines pulling from the same tank(s) at the time of the problem? Since both motors show symptoms unlikely it is the fuel pump. If the fuel is clean in the filter then I second the thought that it is a check valve, the tank venting, the pickup tube or the fuel line. How much of that stuff was replaced when you were messing with the tanks/engines?? Assuming the fuel is clean/dry one way to eliminate all the plumbing is get an outboard tank and run off that.

[JUST-IN-TIME]

best is to run it off an aux gas tank

if she acts up still you know it is on the motor

[Albiebac]

This is total bullshit!!! I have the same exact problem!

I've been dealing with this for the last two years. I've done it all and I'm ready to buy a new motor, if I could just blow up the one I have.

My symptoms (as recent as yesterday):

Boat starts up and runs fine, running at 20 knts it starts to bog down after 30 minutes. Engine sounds like it's working hard and RPM's drop until it falls off plane. Sometimes it'll fix itself and go. Yesterday I was limited to 2000rpms (8knts) and continued on my way going to the 9 and then the 302 trolling. After fishing (successfully) I was able to run for 30 minutes...then same deal, this time the engine had some decent vibrations above 1800 rpms. Shut here down for 15 minutes, then started back up and ran fine for 20 minutes. Then she bogged down again, did the last 5 miles at 8 knots into Mission Bay. Under no load she's fine.

What I've done:

Rebuilt top end
Rebuilt carburetor
Emptied tank
Removed anti-siphon valve
Installed electric in-line fuel pump
Replaced mechanical fuel pump (THE OLD ONE HAD A BROKEN VALVE, YES THEY DO DEGRADE WITH THE GOVT. MANDATED FARMER WELFARE SYSTEM CRAP ADDED TO THE FUEL!!)
New plugs, wires, cap, rotor.
New racor fuel filter
New fuel lines
Auxilary tank (new)
Breather line checks out OK

I'm wondering if it's a temperature thing. Motor seems to get hot (175) then does this. Normally it's 165-170. It's a FWC system, so not much leeway there, unless I go raw water cooled. Yesterday I tried to convince myself it's a timing issue. Advance, loose timing chain, worn cam, worn distributor, bad electonic module...???

As you can tell, I'm thoroughly disgusted with this problem, and I believe it has everything to do with the ethanol....

Let us know IF you figure it out. I say big if, because I think you'll be chasing your tail, just like me.

Best of luck, Eric

[Outlawman]

Originally Posted by Albiebac

This is total bullshit!!! I have the same exact problem!

As you can tell, I'm thoroughly disgusted with this problem, and I believe it has everything to do with the ethanol....

Let us know IF you figure it out. I say big if, because I think you'll be chasing your tail, just like me.

Best of luck, Eric

I feel your pain bro!!! I've been filling up normally at Costco locally and was there today filling my Suburban. While there I asked the attendant for the fuel specs and learned that their gas has 10% ethanol.

I've also noticed that my engines seem to be running hot, as in I cannot leave my hands on the new risers for more than a second or two, even though I'm raw water cooled with 143 degree thermostats...

[SOUTHWEST]

David and Eric: Does your fuel pick-up tube have a screen and have you inspected it for debris? A few years ago my boat experienced the same symptoms. I isolated the problem to one tank and had it polished. This didn't work. I talked to an additive guy who told me to pull the pick-up tube and look at the screen. The screen was covered with "stuff" (looked like fiberglass); there was no way enough fuel would get through at cruise speed. No problems since.

[gecsr1]

Quote:
Originally Posted by gecsr1
Can you switch the tanks to the engines, and see if the tank is the problem or if it's the carb engine. Actually change the inlet fuel lines to the engines .

Say what? Did you happen to read this before hitting the button? Sorry but that's just not clear... thanks for trying tho.
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. Sorry for not being clear, It seemed to me that you were not sure if the problem was the engine (carb Problem) or the fuel Tank problem). I meant to say simply switch the fuel inlets from the tanks to the engines, and see whats happens on a sea trail. If the problem changes to the other engine it's a tank problem, if it doesn't it the carb or a problem with engine that gave you fits the first time...

and I did read it before I clicked send... I guess I could have been more clear.

[scuba e]

you will need to install a vacuum gauge in the fuel system. 1st before and then after the water seperator. if you develop vacuum when under load and the gauge is between the filter and tank then you have a tank or line issue.
You dont have the old grey fuel lines do you?

sounds like you have a cooling issue to. no fuel should make the elbows hot.

[Dirtguy]

Many issues here.
1) Both of you guys , it sounds like a fuel starvation issue. You might need to have someone verify the float level and or metering rod acutation. But start with the basics. You need to do a "fuel volume test." This is to determine if the pump can supply the needed amount of fuel or not. I can tell you how to do it, but if you're shaky about dealing with fuel, get someone to help. But let me let you in on a secret. The guy that will do it for you , might not do it any better than you can.

2) Who recommended that you rebuild the top end for this symptom??!?! Not the cam, chain, crank or valves. A cam issue will be a cam issue ALL THE TIME, NOT come and go.

3) Jack the base timing up a couple and it will be happier with a leaner mixture. Run cooler too. Listen for pinging or pre-ignition.

4) My advice? Get rid of the mechanical pump. Period. Stop arguing. Possible vapor lock issues with the lower vapor pressure fuel. And the ever present devil, "Ethanol!"

5) Wrap your hard fuel lines from mechanical pump to carbs with some insulation. Heat sleeve, foam tape, or A/C insulation for a TEMPORARY fix and/or check.

6) The EXHAUST riser will get hot. It is 700+ degree temp?

dg

[Outlawman]

Originally Posted by gecsr1

Quote:
Originally Posted by gecsr1
Can you switch the tanks to the engines, and see if the tank is the problem or if it's the carb engine. Actually change the inlet fuel lines to the engines .

Say what? Did you happen to read this before hitting the button? Sorry but that's just not clear... thanks for trying tho.
.
.
. Sorry for not being clear, It seemed to me that you were not sure if the problem was the engine (carb Problem) or the fuel Tank problem). I meant to say simply switch the fuel inlets from the tanks to the engines, and see whats happens on a sea trail. If the problem changes to the other engine it's a tank problem, if it doesn't it the carb or a problem with engine that gave you fits the first time...

and I did read it before I clicked send... I guess I could have been more clear.

Thank you very much for clarifying. Yes, I've done that but seem to have a problem no matter which tank I'm on... I'm just pissed!

[Outlawman]

Originally Posted by SOUTHWEST

David and Eric: Does your fuel pick-up tube have a screen and have you inspected it for debris? A few years ago my boat experienced the same symptoms. I isolated the problem to one tank and had it polished. This didn't work. I talked to an additive guy who told me to pull the pick-up tube and look at the screen. The screen was covered with "stuff" (looked like fiberglass); there was no way enough fuel would get through at cruise speed. No problems since.

Good suggestion, as I didn't even realize that there is supposed to be a screen on the pick-up tube. Accessing the main with an auxilary in the way is going to be a f'n bitch...

[Dirtguy]

Maybe a picture of the pump/line arrangement? Have you run it with the covers open/off?


dg