The 1872 starts very hard, why?
 

When first trying to start the cub after it sat for about a week I cranked and cranked and cranked... occasionally it would try to start and then kick the starter out with out starting. I checked the fuel filter it was full of fuel I lightly pressurized the tank to get fuel to the carb still no start. As a last resort I gave it a shot of ether still didn't start until I gave it a few more shots then it finally hit but acted as though it was really starved for gas (barely running) but finally took off and ran good. I let it run for a few minutes turned it off and checked the spark plugs one was gapped at .035 the other at .025 I gapped them both at .025 like kohler specs said. They were a little carboned up but over all looked to be in good shape with no signs of oil fouling, to lean etc.The electrode was like new. I then grounded them to the block and turned the engine over they have a nice blue spark. You would think if it were a fuel problem then it would have started when I first sprayed it with ether and if it were a spark problem then I wouldn't have the good blue spark. When its running it purrs like a kitten and when I give it the throttle it roars like a lion. What am I missing, what are some of the issues that the magnums had as far a starting problems.

looks like your cub caught the 1872 flu that's been going around. i think your the 4th member i've seen in the past 2 weeks with the same issue.

i hope mine doesn't catch it.

It wasn't to long ago I was telling that to A Cecil. I think there is something going around it must be getting spread through this forum LOL. Good luck with yours.

Something definitely going around with the 1872's. My buddy checked today and my 1872 hardly had any spark. Going to have the ignition module replaced.

Did that cause it to be a yellowish spark or was still a good blue spark?

My experience similar to yours turned out to be crud in the tank, line and carb. Not enough to keep from running but enough to make it real hard to start and make it run hot due to being lean. Buy a new plug but check the fuel and carb too. Get a good clear glass jar and let all of the gas drain into it and let it sit for a day to see if you have any sediment in it. Do it before the filter just to be sure that it is there or not. Then if it is, clean and flush the tank, get a new fuel line/filter and clean the carb and all of it's orifices.
Good luck:beerchug:

I have placed electric fuel pumps on my supers and it has taken care of the same type of starting issues that I had as the carburetor is now full of fuel before attempting to start. Also I always bring the throttle up 1/3, start cranking the engine over and after it gets up to speed (3 seconds) then pull the choke out until it fires, then partially push it back in and they usually take off and start.

When it's cold out everything plays a role. I assume you have good gas (not some from last summer), the battery is strong and winter oil in it. When it is running and the hydro is in neutral (no brake on) does it sit there or want to move? If it moves a little forward or back it needs adjusted or it will drag when starting the engine.

Basically with a centrifugal type starter drive, once the engine fires once and does not continue to fire and start, the initial cylinder fire takes the load off of the starter and the engine will throw the starter drive out. It's a common problem especially in the winter and is why most starters now have a solenoid to hold the drive in. Hope some of this may help!

Thanks for the info guys! Its a new day I'll do some more tinkering based on your info and see what I can figure out. I'm still curious if it was a fuel problem shouldn't the starting fluid allow it to at least hit? I did some torqueing of bolts on the intake manifold and carb last night the manifold bolts were a little loose (vacuum leak)? The engine had already been run so of course it fired right up I'll see if it helped at all today after sitting. Its funny the seller said it was really cold blooded he didn't say it was near impossible to start I guess I should of asked for clarification. Of course when I went to go look at it he had already started it so it started right up for me.

Yes, it should fire on starting fluid, although it like gasoline has a shelf life. We don't any more, although in the past inflated truck tires and started the old 2 cycle Detroit's with it and found if the can was a year or more old it had went bad. Don't recommend using starting fluid on your Kohler and should not need to. Just need to determine the hard start issue and repair. Even though the fuel level in the tank is higher than the carburetor, it will not free flow fuel through the fuel pump and if the fuel in the carburetor evaporates due to the engine being warm when shut off, an electric fuel pump will refill it before starting. I have a JD 318 and before I installed an electric fuel pump, if it sat for over a week (summer and winter) you had to crank and crank to get started. Now I just turn the key on, wait 5 seconds and start it right up. If you decide to install an electric fuel pump be sure to get a low pressure one (3.5 pounds or less) otherwise the needle/seat in the carburetor will not control the fuel level in it!

I agree about the tank and fuel flow that was proven to me on my 1811 with m18 if fuel was below 1/2 tank it took forever to get the pump to pull fuel to the carb so I'm sure this 1872 has the same issue. Do you by chance know the part number of the pump you use?

NAPA carries several. This one is 1.5 to 3 pounds. Just wire in at your hour meter.

http://www.napaonline.com/Catalog/Ca...058_0417102348

I had the very same problem on my 1541 replaced mechanical fuel pump an it starts almost instant..

ok thanks a lot guys :beerchug: There is one thing I'm going to try first to prove or disprove a fuel/fuel pump theory I'm going to plumb in a primmer bulb just to see, I'll post results

Here are a couple other electric pumps that should work.

http://www.summitracing.com/parts/mrg-12s/overview/

http://www.summitracing.com/parts/pfs-10701/overview/

http://www.speedwaymotors.com/search...uery=910-11520

One nice thing about going electric is that you can also put a switch in the wiring to turn the pump off so that you are able to run the carb dry, then when you want to start it up again you just power up the pump, fill the carb and lighter up. The 2182's have electric pumps and it works sweet. I may put electric pumps on some of my other stuff this spring.

Looking at the pressure ratings I think Professional Products 10701 may be the best choice of the pumps I've listed here are some other vendors selling them
https://www.google.com/#q=Professional+Products+10701

If it is really cold, slow cranking produces less power produced by the flywheel for the coil on the electronic ignition of the M-18's
Reduce your plug gap to .023-.025, change to 5w30 and and start with a closed throttle.
You might try removing the plugs when it is cold and crank it over,you will see
little or no spark, affirming the no start condition.
Aftermarket replacements are more prone to this than genuine kohler ign. units in very cold temps.
a full battery or jumpers, and some kind of heat helps starting.

Again, If you decide to install an electric fuel pump DO NOT GO OVER 3.5 POUNDS OF PRESSURE as the needle/seat will not control the fuel and IT WILL FLOOD OVER!

I use a boat fuel tank with primer bulb on my Kohler stand by generator. It will bring fuel up to the fuel pump but does not seem to push through it very well. Are your plans to remove or go around the fuel pump and prime with the bulb? FYI the seat for the needle/seat in the carburetor has a smaller hole for fuel pumps over gravity feed ones so it may take a little work to fill a carburetor with a primer bulb.

Update
 

I did the primer bulb test and it took no time at all to start the 1872. I put the primer in front of the fuel pump as a means of testing the pump and like I said it started with no problem. As pointed out by Clint a mechanical fuel pump would probably fix the problem but also as pointed out an electric would also do the trick and has been proven as a good reliable upgrade. I'm thinking I'm going to go electrical the mechanical s seem to be a week link in the kohler engine as I already experienced in my 1811. All though I received great advise on pumps I'm going to go this route its in stock and close by. http://images.oreillyauto.com/parts/...g/42s_pack.jpg When I get the electric installed i'll do an update with pictures Once again thank you guys for great advise :beerchug:

Looking forward to your update! The fuel pump was replaced on my 1872 a year ago, but it's the mechanical one.

What is the psi rating on that pump?

Looks like it is 2 to 3.5 Sam.

That should work. reason I asked is they also have on that is around 7PSI, that would be a bit much and could cause flooding.

:High5: What cub crazy said.
I went and picked it up on the way to work and will be installing it tomorrow morn.

Cool deal! Can't wait to see how it works for you.

I got the electric pump installed today ,I cant say it started right up but it did start a lot easier. It will take a few times to figure out the combination that works best. It took about 3 hous to complete the Install that included changing out all the fuel lines, wiring, drilling and mounting Heres some pics of the finished product.**** pictures are not turned in my photo album not sure why it does that sorry.

Looks good!:beer2:

Here's what works best for me starting my 1872, 2082:

Turn the key on and wait on the fuel pump for about 5 seconds or until the fuel pump quits raddling so hard, bring the throttle up 1/3, start cranking the engine over and after it gets up to speed (3 seconds or so) then pull the choke out until it fires, then partially push it back in and they usually take off and start.

I have found that if you do not bring the throttle up (off idle) or pull the choke out before the engine is turning over they start harder and it usually take several attempts to start them. This same procedure above also works best for my 2182's, 2084 & 2284 .

Great job on the install!

Thanks Allen I hope yours is fixed now.
Thanks cucrazy
CCpullin I'll give that a try thanks again for all the advise

Woody - Sorry for your hard start troubles. Some comments that may help.

Plug gap - As per the Kohler Magnum manual, the correct gap for the spark plugs is 0.035". There is a Cub Cadet owners manual that contains a misprint and calls for a smaller gap. The smaller gap does not produce as much energy and the Magnum can run quite poorly at this smaller gap that Cub printed. (I am deliberately not stating the incorrect gap to avoid confusion; no reason to repeat wrong information.) Early on my Cub journey, I got fooled by this misprint and I can tell you it makes a big difference in performance.

If you were to need to reduce the gap to obtain spark, you would need a new magneto. This doesn't seem to be your problem, but these threads live forever and I don't want anyone in the future gapping their plugs incorrectly. The Kohler Magnum Service Manual is available on their website.

As for your electric fuel pump, it looks like you did a nice job, but it is mounted too high. Most electric fuel pumps, as with this one, need to be gravity fed. Ideally the pump should be mounted below the fuel tank, and at worst, even with the bottom. These styles of pumps are very good at pushing fuel but do not create strong suction. They are also sensitive to dirt and that is why Mr. Gasket so kindly gave you a filter; many electric pumps have failed due even a small amount of dirt.

I would recommend that you find a mounting point below the tank and make sure you keep the filter on the inlet as you have done. If you keep it where it is at it may not pump properly when the fuel level is low and you may have the pump wear out prematurely.

The other comments from others that might help are about cranking speed. If you are trying to start it at temperatures below 30* you may have difficulty without a real good battery, good electrical connections and you might need thinner oil such as 10W-30. If you go with the 10W-30, you will need to switch back to straight 30W in the spring. Magnums will consume multi weight oil when it is warm and carbon up the combustion chamber.

Tom thanks for the info, Where were you a week ago LOL. It so happens I am running my plugs at the misprinted gap but since the fuel pump install it hasn't been an issue as far as starting. But I will go back and correct the gap because I want it to run at its peak performance. I saw in the paper work for the pump (after the fact)that it was a gravity feed so I drained the tank down to see at what point it would starve for gas it seems good until about an 1/8-1/4 of a tank. One day I'll move it down so the top hole of the bracket goes to the bottom drilled hole (about 2 inches) I think that's about all the room there is so I may have to live with it, I'll take another look tomorrow. As far as the colder temp goes I was aware of the affects that can cause and heavier oil not helping it to crank any faster, but for me in this case the tractor has been in a garage which is kept about 50 deg when I'm not in there so it was a none issue It cranked very well. But certainly great input for someone that may be having a starting issue.

I went to use my 1811 today here in Atlanta to haul a load of 2x4's, the temp is about 40 F, and it would not start. I jumped it with a charger and it cranked right up. It has been sitting for about a month and has summer gas in it. I'll run the rest out and then give an overhaul this winter. I have not checked the plug gap but I will. Thanks for the info about the misprint in the manual. I can see how thick oil, cold temp on the battery and old fuel can make a hard starting M18.:beerchug:

Here I am about a month later right back in the same boat the cub has been sitting outside inthe cold and it will not start it wont even try to start It turns over pretty fast (the oil is winter oil) its got freash gas in it. Its got a nice blue spark , the plugs ate gaped at .035, its got a new electric fuel pump, I poured gas right in to the carb and it wont even hit.Is there any timming to these motors? What controls the timming of the crank to the cam is there a chain? What else could be the problem if it gets gas and has a good spark all thats left is timming?

Just my two cents,but if it was a timing issue it would be popping back through the carb.If its getting a good spark and getting fuel INTO the combustion chamber it will run.Four things are needed to make an engine run,timing,spark,fuel and air.If all four of those are present it will run.It just sounds to me as though the fuel is not getting past the carb jet and into the combustion chamber.I would pull the plugs out pour a VERY SMALL amount of gas into the cylinders,maybe four or five drops,replace the plugs,spin it over and see what happens.If the plugs are good and getting good fire it will either start and run for a short time and die,backfire or spit back through the carb.May not be a technical way of doing things but it has always worked for me.:GoodLuck:

Thats what I was thinking about the timming it doesnt back fire when it runs it runs very well I did pour some gas in the carb didnt fire I'm also wondering about a vacume leak at the intakecould be a possibility?

Many posts back I suggested to close the gap on the plugs to .023-.025 and try to start it, have you tried that?
If it starts it is the coil/ign unit that is weak.
If it don't start, what have you got to loose?
BTDT

Your right and my apologies I didnt mean to ignor that advise I thought I had it fixed I will go back and give it a try

You say it has a nice blue spark, but the problem is, what happens outside the engine doesn't necessarily mean that is what happens inside the engine, under pressure.

:bash2::bash2::bash2::bash2: I went out this morning without touching any thing but the key and it started right up I repeat :bash2::bash2::bash2::bash2: The only difference is it sat in a 40ish degree garage since I drug it in yesterday from 18 deg cold. If its true the "coil/ing unit" is affected by temp then that was the best test you could give to prove or disprove that. I just wish it wasn't such a P.I.TA. to change it Or I would have done it along time ago! Can I replace this without pulling the motor??

That's true but its always been a pretty good way to help to test starting issues. Do you know of a way to bench test a ing module/coil from the kohler engine?

Guess it doesn't like being cold, just keep it nice and warm inside. :beerchug: