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Discussion Starter · #1 ·
I've got a 1982 Polaris TX-C 440 chassis with a 1974 Kawasaki 400 engine from a '74 El Tigre. Both were free! I am trying to make a sled I can putt around on on the cheap side.

  • Top end looks good
  • Good compression (I don't have a tester but it feels real good on the recoil)
  • New spark plugs
  • New fuel lines
  • New fuel filter
  • New fuel pump (diaphragm)
  • Amsoil 40:1 fuel ratio (for starters)
  • Cleaned the fuel tank
  • Cleaned up the carbs real nice
NEED ADVICE!

Guys it starts hard. If I am able to get it going, it wants to die. To keep it running I have to feather the throttle. If I floor it, it bogs and wants to die. If I don't lean into the throttle hard enough, it also wants to die.

While managing to keep the engine alive, I took some starter fluid and sprayed it at the crank seal on the PTO side. No change. I sprayed it at the right carb boot. No change. I sprayed it at the left carb boot... And suddenly the engine picked up and ran really well. It seemed to have power. I ordered a new boot for that side.

Little side note: my fuel lines have a few air bubbles in them... I think I should do a better job of bleeding them. Maybe some compressed air through the breather port on the fuel tank?

What more should I look for?
 

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Don't worry about the air bubbles. They work themselves out. As the fuel goes into the carb, the air will just get vented out.

I'm still having an issue with my 89, which has a butterfly carb. I know the carb needs a better cleaning, but I know these carbs are a lot more finicky to tune. Figuring on letting my brother do it (he's older!, haha).
 

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Discussion Starter · #4 ·
Thanks for the advice guys!

I think I have both carb boots good and tight now. I tried running the engine, but it ran poorly as before - very boggy at all RPMs and wants to die with no idle.

I found that the crankcase drain was out, dumping fuel on the mounting plate and sucking in air. That will explain a lot! I found a drain plug and threaded it in.

Now, the engine runs very nicely on universal starting fluid if I spray it into the carbs. (I was careful not to do this for long, because the engine is then not getting lubrication.) Without starting fluid being sprayed into the carbs the engine will not run.

I detached the fuel lines from the carbs, put them into a clear container and pulled the recoil over. A lot of clean fuel/oil mix pumped into the container from each hose. I think my brand new diaphragm fuel pump is healthy.

CONCLUSION:

I think I have narrowed (at least one of) the problem down to my carbs. I do believe they are very clean. Any pointers guys? What should I look for?

Thanks!
 

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Discussion Starter · #7 ·
I would check the needle/seat inlet in the carbs. If you have fuel to the carbs but nothing is getting to the engine, that would be my first place to check.
Thank you sir,

I found the bowls full of fuel. One main jet was 90% plugged. The needle/seat area was plugged on the other.

Now my engine runs AND idles (pilot jets are clean)!

This is my first snowmobile. Any advice for breaking in an old engine? I've heard people say to run 40:1 fuel-oil mixture for a while and don't lean into the throttle too hard at first. I am going to do these things.
 

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He said he is running a 74 Kawasaki 400 engine in this sled. It will not have oil injection from that vintage. He will need to run pre mix in it. 40:1 sounds about right for that vintage of motor. If it did run 50:1 then you will just have a little more smoke out the exhaust.
 

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Discussion Starter · #12 ·
I am using Amsoil which I believe is supposed to be the best. If and when I get it broken in some, i'll switch over to 50:1 which I believe is what is on the label. I am NOT going off what the operator's manual recommended (from what I read it sounds like it was probably around 20:1) because oil apparently has changed a lot over the years. I'm NOT an expert though.

And yes, this engine does not have oil injection.
 

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Discussion Starter · #15 ·
Making gains here. It runs and idles now, but not without difficulties. This thing starts so hard! It seems as though it floods super easy. To cold start I have to no-choke, hold the throttle wide, and recoil 20+ times. That's how this one starts.

Driving is another story. With it on the stand, it bogs when I floor it, but pulls out of it and seems to make good power at the top end. I took it out of the shop for a "test drive" the other day. It bogged super hard out of the hole, barely getting going. 500 ft later at a turn it bogged to death. I guess if it bogs on the stand, you can bet it'll bog in the snow!

  • Air screw is set to stock (1 turn out from dead-end)
  • Pilot, needle, and main jets are clean
Rectangle Font Parallel Screenshot Number

  • Main jet I have is a 270, NOT A 360 LIKE STOCK
  • Pilot jet is a 25
  • I live in frigid Manitoba if that helps with jetting suggestions

Messing with the air screw in or out did not seem to change the bog on the stand.

Any idea why I have to start the engine this way, as if it's ALWAYS FLOODED? (My float seems to be working)
Any idea what would cause a bog EVEN ON THE STAND? (Clutch?)

Thanks for your time!
 

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Do you have a fuel shut off
Put one in!
Mean time needle nose vise grip the fuel inlet to the pump
Remove the plugs
Kill off Pull it over till No mist of fuel
Put fresh plugs in and see if it will start
Then remove vise grip
 

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Discussion Starter · #19 · (Edited)
Do you have a fuel shut off
Put one in!
Mean time needle nose vise grip the fuel inlet to the pump
Remove the plugs
Kill off Pull it over till No mist of fuel
Put fresh plugs in and see if it will start
Then remove vise grip
I do not have a fuel shutoff.

A couple days ago, I put a needle nose vise grip on the hose between the fuel tank and the diaphragm fuel pump. When doing so, I noticed a slow drip coming from the bottom of the bowl on the right carb. Interesting... I am 96% sure my floats are working...

Hood Motor vehicle Car Vehicle Automotive fuel system


And now, TODAY I removed the plugs, and recoiled the engine about 12 times. No fuel came out of the plug holes at all. As these plugs are brand new I dried them off (they were wet) and put them back in. I recoiled (kill switch set to RUN) about 10 times. The first pull it fired or coughed a bit. Not much after that. I removed the vise grip and then tried starting on medium choke setting. It finally started when I gave it a little bit of throttle. Trying again, I confirmed that a little bit of throttle gets it going on startup. I put vise grip back on when I left.

Needle and seats not sealing properly??
Needle jet and needle worn??
 

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Umm If that is a single outlet pump you have the wrong pump on it. It needs to be a dual mikuni pump not the single. It is most likely starving for fuel. Get one like the one below at amazon or some other place from mikuni.

 
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