Fuel Troubleshooting

[SurfBeat]

I installed a replacement crankshaft, cleaned the filters in carbs (the carb looked new when I disassmebled it), I don't have gray fuel lines, my inline filter is clean, and this afternoon after I put everything together and tried to crank the engine, though it would crank, it would not start.

I checked the "in-line" filter and it was dry, so, something is amiss.

I put two gallons of fresh mixed gas in the tank, so, in my opinion, that amount should be sufficent for the fuel pump to draw the gas from the tank.

What am I missing?

On a side note, after reading several threads regarding similiar problems, I wondered, did I hook up my return hoses correctly!

To facilitate answering that question, I have a attached a photo. The long hose on the far right (1) comes from the fuel filter and the one on the far left (2), is also from the filter.

I sucked on line #1 and the fuel bowl filled with gas, however, when I attached it to the carb, I got nothing.

I've read in the forums that it takes a while for the fuel pump to create a vacuum to failitate pumping, so maybe I am not waiting long enough??

Whatca think?

I am so close to heading to the River, but also so far away!

 

[SurfBeat]

Back again after reading soem more threads.

I read a thread wherein the Thread poster stated in relevant part that some "book states to prime the carb after a rebuild by blowing through the "return" fuel line until fuel starts to come out the fuel return fitting on the carburetor."

Okay, the Thread makers did not state which" book" he was referring to, nor did he explain what return line to blow in to.

There are two gas lines coming from the gas tank, one to the MAG carb via the filter, a second to the PTO filter.

Is one of those lines the one which I should blow into to get fuel flowing?

 

[Dr Honda]

The carb uses a simple diaphragm pump, and it doesn't need to be primed. Normally, if the system is dry, it will draw fuel up in about 5 to 10 seconds of cranking.


The picture has a glare in it... but it looks OK. If you have verified that there is fuel on the incoming hose, then I would put a little pre-mix fuel down each carb, and start the engine. At running speed... it should pull fuel instantly.

 

[SurfBeat]

It appears from your reply that the engine has to actually start/run, rather than crank to suck fuel to the engine? Yes?

I was reading some Threads last night on the subject in question and one related that a problem that I am experiencing can be caused by the mechanic (me, ha ha) failing to align the Rotary Valve accurately, and to verify oen way or the other is to disconnect the impulse line and feel for suction and blow. If both exist, everything is 10-4.

If not, trear it apart and do it right.

Another thread referred to a bad fuel pump.

Is there a quick check to ascertain whether the pump is sucking, i.e., disconnect the fuel line from the pump, crank and check for suction?

So close, but also so far away from starting this Doo.

At least it cranks, so, I know I performed part of the task properly.

 

[DonoBBD]

A little trick that works better than dumping in mixed fuel is start her on propane. Just a small torch not lit and hold it running in the intake. She will start and run on it and suck up the fuel real fast.

Cheers Don.

 

[SurfBeat]

How can I verify whether my fuel pump (FP) is functional?

Can I simply remove the gas line that attaches to the FP nipple, put my finger over it and as I crank the engine check for suction?

I am not getting any fuel to the fuel bowl, thus nothing to the carb. I've searched the Threads for similar problems and they focus primarily on cleaning the carbs or replacing the fuel lines.

My carbs are clean. The fuel lines have no obstructions.

The issues is suction, getting fuel from the gas tank to the carbs.

What do I do to troubleshoot this problem?

PMS: Has anyone tried the propane suggestion as suggested in a post to this Thread? It appears dangerous, but???????

 

[SurfBeat]

I found this post to a Thread by the Voodoo Man which I found helpful to me in my quest to troubleshoot fuel delivery problems relating specifically to the fuel pump.

According to VM, "the fuel pump works from the pulse of the crankcase pressure.

[T]here is a line on one end of the motor that goes to the carb, this place will be labeled pulse.

f your kids are young and you have one of those squiggly drinking straws put some water into it and connect to the line you take off the pulse port - the water should move back and forth in the straw when you press the start button - this action works the pump diaphram to draw fuel from the tank/control/water-fule filter bowl into the carbs.

t is possible your carb basket filters are jammed with steel [sic] gas can trash and nothing can come thru.

If you pour a coffee shop spoon of fuel into each spark plug hole does the motor run on this and then go soft?

Next would be to check the rv valve timing to be sure the carbs are in a vacuum at the correct time in the cycle - this will also mess up the pulse so check it first - no pulse go into the rv cover.