425 Won't Start

hogi · Nov 29, 2007

I have a 425 with very low hours (<20). It has been sitting for a couple of months outdoors. It wouldn't start so I put some fuel in it- it was low, and used some starter fluid and finally got it going. I the started and stopped several times after that, it started OK but would run-on at shut down. Now I cannot get it to start, even with the help of starter fluid. I did notice some dark colored contaminate at the bottom of the fuel tank, kinda darker colored and separated from the fuel, heavier. I'm sure it's a fuel related problem, any advise from anyone that's dealt with bad fuel before would be greatly appreciated. I did pull the line comming out of the fuel pump and got a steady stream of fuel but there is a lot of air in the filter.

Gravy · Nov 29, 2007

Hogi,

When you turn the key to the "on" position, can you hear the fuel solenoid in the carburetor operate? It should be a pretty distinct clack. If it is stuck closed or clogged, or if the wire came unplugged, the engine will be starved for fuel. You could also have the opposite problem - if the engine is flooded, maybe due to a stuck float, sometimes starting fluid doesn't help. The running on might fit with that. Did you see black smoke from the exhaust? If so, it's likely flooded.

Also, I've been bitten more than once by assuming there was a fuel problem, so you may want to check for a good strong spark. Weak spark can cause symptoms that seem like fuel problems.

Several of us have had with fuel supply issues in the first few hours of operation. You may need a to clean the fuel system. Drain the tank, remove it & clean out the plastic/adhesive bits that may clog the outlet elbow. Mine didn't look plugged, but it was. I'd suggest replacing the fuel filter with a bigger one.

If that doesn't clear up any fuel problems, you may need to take the top off the carburetor & clean out the float bowl, pull the fuel solenoid & clean the main jet. On mine, crud from the tank somehow got past the factory filter and caused running problems. If you've worked on automotive carburetors, the Robin one is pretty simple, although I recall that getting the float & needle back in place was a delicate task.

Fortunately, the crud cleanout seems to be a one-time issue for most.

Hope this helps. Keep us posted on how it goes. Good luck!

Gravy

BobRip · Nov 30, 2007

Hogi, I would drain all of the gasoline out of the tank, fuel filter, fuel lines, pump, and carbuetor in addition to the suggestions from Gravy of course. The PT are not really designed to sit outside in the rain and dew. I suggest you at least cover it from now on.

ponytug · Nov 30, 2007

You may want to add a little dry gas to clean things up when you are done.

To help clean the gas, West Marine sells a pretty slick fuel funnel, with a teflon coated stainless steel strainer that removes crud above about 20 microns, and includes a sump to accumulate heavy particles, water, and sludge. It will reject any droplets of water, but it won't help you out if there is a bunch dissolved, via dry gas.

It isn't a bad fuel funnel either, if you don't have a CARB compliant gas can.

I think the same or similiar product is on the web as Mr. Funnel, but I believe that the sump is not as large.

hogi · Dec 4, 2007

I went back and tried to start the PT and listened for the fuel solenoid, but didn't hear it so I started checking all the wiring, thinking it was an electrical problem. Everything was checking out OK, so I finally pulled the solenoid from the engine and turned the key while grounding it, it pulled the plunger in but not with an immediate jerk. I re-installed it and the engine started right up. Then I went about putting back on all the covers air filters etc, I tied back down all the wires and went to start it- and of course it wouldn't start. I pulled the solenoid again, checked it again, reinstalled and it fired right up and ran great. I adjusted the throttle and choke cables, they were way off as I believe someone else has mentioned before. Ive started it several times with no problems. The bottom line is, I don't know where the problem lies but it runs now. I suspect I might have underlying electrical problems that I cannot find. Should the plunger on the solenoid pop back when energized or is it accepable for a gentle pull back?

J_J · Dec 4, 2007

hogi said:
I went back and tried to start the PT and listened for the fuel solenoid, but didn't hear it so I started checking all the wiring, thinking it was an electrical problem. Everything was checking out OK, so I finally pulled the solenoid from the engine and turned the key while grounding it, it pulled the plunger in but not with an immediate jerk. I re-installed it and the engine started right up. Then I went about putting back on all the covers air filters etc, I tied back down all the wires and went to start it- and of course it wouldn't start. I pulled the solenoid again, checked it again, reinstalled and it fired right up and ran great. I adjusted the throttle and choke cables, they were way off as I believe someone else has mentioned before. Ive started it several times with no problems. The bottom line is, I don't know where the problem lies but it runs now. I suspect I might have underlying electrical problems that I cannot find. Should the plunger on the solenoid pop back when energized or is it accepable for a gentle pull back?

The solenoid uses 12v to pull in, and a spring to return to rest, so you may see fast pull in and that is the click you hear. The spring return might be a little slower.

The solenoid should activate as soon as you turn the switch. The purpose is to allow fuel to flow, by activating the solenoid, or shut off the fuel in the release position. You may still have some gum residue remaining. I would spray carb cleaner on it while activating the solenoid many times. If that doesn't fix things, a new solenoid should be considered.

You may also have some water in the tank or bowl, this will cause starting and running problems. I remember one fine day while trying to cut grass, I must have taken off the solenoid and bowl 5 or 6 times, and every time, there was water in the bowl. Honda has the right idea, they put a carb drain screw in the carb bowl.

ponytug · Dec 4, 2007

The fuel solenoid should snap right in. You can try some carb cleaner as JJ suggested; if it doesn't work, and if the contacts are clean, it is probably dying, and you should replace it.

I'm glad you got it starting.

All the best,

Peter