78 intruder runs then dies when warmed up

[intruder440]

Hi, new to the form and kawi sleds. I just bought this sled (78 intruder 440) and can figure it out. It runs and idels well. when i go to ride it i can go for maybe 2 min then it dies and wont start untill its cold again. I still have spark when it dies. iv put new plugs in it. Any sugestions? Cranks seals? Thanks

[Interceptor398]

Welcome to the site!!!  First thing I would do is drain the gas and change ALL the lines connected to the fuel pump.  That will eliminate most of the fuel issues and I suspect that is what you are dealing with.

[intruder440]

All the fuel lines are new just before I got it. The fuel pump doesnt sit in the holder bolts, only on the one side so its crooked. could that have something to do with it? Ill try fresh gas tomorrow. What would you recomend for fuel mix ratio? Thanks

[Interceptor398]

Is it the tall fuel pump and is the pickup line in the gas tank in good condition?

[mswyka]

Based on what is posted so far I have to believe that this is a fuel issue.  I understand the sled has spark even after it dies so I want to rule out bad coils.  But just to be sure, how did you determine that  it has spark as it dies?

So on to fuel:  When you  start the sled do you need or use the primer?  And, after the sled dies, if you use the primer can it be restarted?  I am asking these questions to try to eliminate a bad or blocked fuel tank vent.

How much of the sleds history do you have?  Have you thoroughly checked the carburetors?  Do they have the correct jets?  Are the power jet lines connected correctly?

Have the crank seals been changed?

There is  a question about fuel mix ratio.  Has the oil pump been disconnected?  And if so, can you tell why?

We have a number of sleds that have come in with the same story "ran last year, just needs carburetor adjustment."  But the story is always the same and it becomes obvious quickly that the sled has not run for several years.  First crank seal failure causes a piston failure, the owner assumed the piston failure was caused by no oil and a failed oil pump so they disconnect the oil pump to run pre-mix only to have another piston failure, at that point they have run out of talent and park the sled.  We have probably had six or eight Intruders all come in with  that same story.  Nothing wrong with the oil pump.  We clean it up, put in fresh crank seals and fresh pistons and away we go.  I am not saying all sleds are like this, but if the crank seals have not been checked, quite a bit of the other troubleshooting may be meaningless.

[intruder440]

hi guys.
 Interceptor398, I believe its the tall fuel pump. The pick up line seems to be good as far as I can tell. After reading your post last night and you figured it was fuel and thinking about it a bit myself I figured I would pull the carbs off and take a look. As I was in the process of taking them off i could see junk in the  one main line. There was a bunch of stuff jammed in the inlet and stuck just before the needle. Ones soaking now and ill clean the other tomorrow and do the same to the fuel pump.

 mswyka, to see for spark I pulled the boot off and stuck a spare plug in it and got my brother to pull it over while I looked  (he didnt want to risk his finger tips).

To start it I use the primer and choke. When it dies I can still prime it but cant get it to start.

Dont have much for history. The guy I bought it from said he had it out a few time and it always ran great. Said he cleaned the carbs but I now know how well that was done... As far as jets go I have no Idea. What should they be and how do I tell? The power jet lines are the ones from the bottom of the bowl up to the top right? If so there both there and look fine.

I have no idea on crank seals. He said the guy he bought it off fixes sleds over the summer and sells them in the fall. I kinda think it was just a quick flip for the guy.

For fuel mix the PO was running 50:1 but I have read somewhere 40:1. The oil pump is disconnected. I have no idea why and is something i would like to look into once i know it runs decent. I think there is a thread on here about it but are they difficult to set up? How do you know if theres something wrong with it?

Thanks

[Interceptor398]

Be sure to syphon the tank empty, that stuff you found had to come from someplace.

[intruder440]

Im going to borrow a friends oil extractor and give it a go with that and see what happens.

[Interceptor398]

I have a hose connected to a rod so I can force the hose to the lowest spot.  Tip the sled up or as I did with my 81 Invader, park it on a snow bank. After you are done draining the tank let the gas sit in the can for a few hours and gently pour all but the last couple quarts into another can.  Pour the last bit of gas into a clear container and see what was resting on the bottom of your gas tank. The jug in the picture is from my 81 Drifter the first time I syphoned the tank.  It ran fine if I had enough gas in it.  When I syphoned the gas out and found out the pick up line in the tank had dissolved and was floating around on the bottom of the tank along with some sand.  It's a pretty simple process and if it's a sled I ride much I will syphon the tank dry at the start of the season so the tank is clean and the gas is fresh. I will do the same thing with my ATV and I drain the gas from my chainsaws if they will not be used in the near future.

[mswyka]

good call on the stick attached to the hose.

As far as starting, if it starts with a prime, but won't start with a prime after it stalls out then I have to believe that there are multiple issues. 

Do you have a running sled that you can borrow parts from?  In addition to what you are finding with  the fuel system I am suspicious of the spark coil.  And swapping in a spark coil that you know is good can either  solve a problem or eliminate an unknown.  Spark coils break down over time and will spark with the  plugs out of the sled but won't provide enough spark under compression.  By the way, what is your compression?

The oil pump is  exquisite in its simplicity.  I think that  the first part of checking it out is to take it off the sled and clean it up.  Take off the end cover to check to see if there is gunk in there.  But don't take out the cylinder.  Spray out the pump and the ports with solvent.  If everything is clean and spins freely, put it back together, add some oil and spin it with a drill.  Well, maybe put some hoses on the output ports so that it does not spray all over.  There is a section of the manual  to measure  how much oil should be pumped.  Do you  have a manual?

[intruder440]

I finally got every thing cleaned out. Carbs, fuel pump and the tank. Had it out for a bit tonight and seems to be running good so far. I did notice I have no lights. When I picked it up  the head light was working, now nothing. I only have a brake like then I pull the lever. Any ideas on that one? Thanks again guys for all the help and knowledge. 

[mswyka]

That is good news.  Glad to hear she is up and running.

For the lights, check the headlight  bulb.  Is it burned out?  If so it may be a bad voltage regulator.

If not burned out, Check to confirm that key switch is in the "run - lights on position". Check the plug between the wiring harness and the engine to make sure that all the pins are seated tightly.  Then check the plug on the back of the key switch to make sure that plug is seated properly.

[intruder440]

Figured the lights out today. It was nice and easy , the key switch was turned1 spot to far. I finally got to take it out for a ride today on the lake. Ran really strong for 10-15 min then seemed to start bogging. It's about 1-2 degrees c here . Is it just not cold enough?

[Boomologist]

Haven't read all the posts about this but a couple things come to mind.
Do you have an inline fuel filter? It may be plugging up if the tank has a layer of shellac in it that is breaking loose. If no filter you may have carbs plugging up again. I always run an inline filter. (be very careful with fuel tanks. Even after they have been pressure washed there is still enough vapor in them to explode! Learned this the hard way)
Are you running an airbox? Without one you may be having carb icing.
Is it possible it's not getting enough oil and may be trying to seize up?
Are you running alcohol enriched fuel? Not recommended for two stroke.

[intruder440]

I put a filter in when I cleaned everything out just to be on the safe side. Can't see any dirt in the filter but it also could be something like you were saying. I have the air box on it. I'm running premium fuel with no eathonal. I mixed the fuel 50:1 plus a bit extra just to be safe. If I let it sit for an hour or do it fires up and runs good for 10-15min then seems to get boaggy/ looses power.