1420 problem - Page 2

maineiac · #11 06-21-2011, 10:13 PM

ok, so why only after it sits for a few minutes? upon restart this occurs, it has never happened on a cold engine.the pump is mechanical, what part of it would fail to give such repeatable symptoms?

maineiac · #12 06-21-2011, 10:19 PM

also, why does pulling the choke on the fully warmed up engine let it start up, I then push the choke in as soon as it starts and it runs fine till i shut it off. I don't want to keep throwing parts at this.

Matt G. · #13 06-22-2011, 07:31 AM

The check valves quit sealing and it won't hold pressure anymore. This is a fairly typical failure mode for the Kohler mechanical pumps. If you have a fuel pressure gauge you can connect to the 'out' hose, you can connect that and crank the tractor (with the spark plug wires disconnected). If the needle on the gauge goes up to 2 psi and stays, the fuel pump is fine. If the needle flops around, the pump is bad.

I'm not familiar with the fuel tank location on the 1420, but if it's higher than the carb, fuel will probably leak past the pump and re-fill the float bowl on the carb.

You don't have to 'throw parts at it'. Replace things in the cheapest order. Start with the fuel line and filters and make sure the tank is clean inside. That'll only cost a couple bucks. It would probably be a good idea to make sure there isn't any garbage in the float bowl of the carb, either. If that doesn't fix it, the only thing left is the fuel pump.

maineiac · #14 06-22-2011, 08:24 AM

OK, sounds about right, I tried to check the fuel pressure one time while this condition was occurring. I hooked the gauge to the inlet side of the pump, not the outlet (I didn't know it mattered), the needle was fluctuating all over. I will try it on the outlet side like you said. I appreciate all the help you are giving me but I still don't understand why this problem occurs in the way it does (meaning after the mower sits hot for 5-10 minutes), again I have not seen this problem on a cold engine. One other thing I though of, I am using a see through universal fuel filter, I notice that when I go to use the mower when it has been sitting cold in the shed, I can see the filter is almost full with gas. After it runs for a while I can see no gas in the filter. I am thinking maybe the suction of the pump is good while the engine is running at high speed and as long as the engine is running it can pull fuel. Maybe after I shut it off hot (there isn't enough fuel in the filter to make it run properly ?) It can fire up and run for a few seconds on the gas that is in the carb but then it starves itself. Do you think an original kohler filter might fix this? Just can't figure out why the fuel pump would only be problematic after the following situation with the mower (i.e. after i shut it off hot and it sits for 5-10 minutes) sorry for the length of this email, just trying to be thorough. thanks

maineiac · #15 06-22-2011, 10:18 PM

somebody please comment on my latest reply, thanks

R Bedell · #16 06-23-2011, 06:39 AM

Well, you maybe on to something that you didn't mention in prior post(s).

The fuel filter does make a factor to deal with.. It matters on (A) the type of fuel filter, and (B) where it is located in the fuel line..

There are two types of Fuel Filters. (1) for a Gravity fed fuel system, and (2) for a Fuel pump fed fuel system.

Gravity Fuel Filters are used in system where there are NO fuel pumps.

The filter used on pump type of systems are installed in the fuel line between the fuel pump outlet and the carb inlet. Thus take and need the pressure of the fuel pump to do it's job.

Matt G. · #17 06-23-2011, 07:29 AM

Roland-

I haven't had any of these lawn tractors, but in every garden tractor I have had with a fuel pump, the filter is before the pump. I imagine that's to keep junk from ruining the valves in the pump.

maineiac-

I more or less answered everything in your other thread in my previous post. I don't know the exact failure mode, but I do know that Kohler mechanical fuel pumps typically suffer heat-related failures. Replace the filter first, but I still think it's the fuel pump.

R Bedell · #18 06-23-2011, 08:04 AM

My point in the previous post was that there is a difference between a gravity flow fuel filter and a pressure forced type of fuel filter. Get the fuel filter that your equipment calls for and install where the OEM recommends.

I do think now from additional information, that you have a fuel delivery problem. The motor runs long enough to starve its fuel supply, then dies. Once the fuel catches up, it will restart. You need to look at all components of your fuel delivery system to see where the starving is occurring.

maineiac · #19 06-23-2011, 08:54 AM

my issue isn't that it dies while running, it is that upon restart after the engine has been shut off for 5-10 minutes, the aformentioned condition is occuring, so it seem like heat is getting to something, (why would a fuel pump only be problematic after it gets hot??) someone must have an aswer to this question.

cuysan · #20 06-27-2014, 08:16 AM

Quote:

Originally Posted by Matt G.

Roland-

I haven't had any of these lawn tractors, but in every garden tractor I have had with a fuel pump, the filter is before the pump. I imagine that's to keep junk from ruining the valves in the pump.

maineiac-

I more or less answered everything in your other thread in my previous post. I don't know the exact failure mode, but I do know that Kohler mechanical fuel pumps typically suffer heat-related failures. Replace the filter first, but I still think it's the fuel pump.

Very old thread but my input may help others with the same issue. I have a 1420 with the exact same symptoms. Checked coil, fuel pump and tank with no luck. Replaced the fuel pump and she runs like a dream again. Matt nailed it on this one. Struggled with it all last season. Replaced fuel pump this season and has been running like a top ever since. Can't answer your question:

(why would a fuel pump only be problematic after it gets hot??)

Can only say it solved my problem.