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Discussion Starter #1
Holy smokes guys, I'm at the end of my wits and I know it's just me being stupid.

Picked up an ultra clean SRV540 at a garage sale for $250. 4700 original miles, immaculate. Only catch: it didn't run. Guy said he put gas in the plugs and it fired.

So that means: fuel problem. Ok, got it. Pull the carb and there's gunk in there almost like a squirrel was chewing up nuts. Vacuum out the carb, the airbox, clean the carb three separate times with carb cleaner and compressed air. Pull reeds, inspect, clean out manifold. Has compression. Reassemble, pull and pull and pull, nothing.

Must be the fuel pump, right. Pull the gas line from the carb, put the end in a water bottle and pull, shoots gas with every pull. Not the pump. Pull the carb, full of gas. Pull the plugs: dry. Not an OUNCE of gas getting to the cylinders. Poured some gas down the holes and pull, fired on the first one. Pull carb, clean again, ensure everything secure, reassemble. Pull pull pull pull nothing, full carb and DRY cylinders. Not a drop of fuel reaching the plugs.

WTF? This just cannot be that complicated. A 1990 SRV isn't space age technology. Somebody, for the love of god, tell me what i'm forgetting. Im going insane.

Thanks
 

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Did you work hr float and see if air came out of there when you blew air in thru the inlet ?

How about the air bleeds ? If they are plugged fully or partia;y fuel won't flow correctly out of carb . I've seen mouse piss corrode bleeds shut, :(

Just asking because one persons carb cleanings can be very different from the others,,,,like my old man's vs mine. He;s just spray everything on the exterior and call it cleaned. LOL,
 

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Discussion Starter #3
Did you work hr float and see if air came out of there when you blew air in thru the inlet ?

How about the air bleeds ? If they are plugged fully or partia;y fuel won't flow correctly out of carb . I've seen mouse piss corrode bleeds shut, :(

Just asking because one persons carb cleanings can be very different from the others,,,,like my old man's vs mine. He;s just spray everything on the exterior and call it cleaned. LOL,
Haha yeah i get you. I pulled ever single piece out of the carb, sprayed with cleaner and air. All jets, idle screw, float and valve, etc. Blew air and cleaner through any and every channel in the carb, including breather hoses. I also just verified the exhaust is free from obstruction. My blood pressure continues to rise :wall:
 

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calm down. you are not missing a big trip this week-end over it. :)
 

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Check to see if the fuel pick up fell off in the tank. I have seen many sleds get sold or parted out because it won't get gas, and won't run, and it's the fuel pick up that sends the gas from the tank to the fuel pump. The clue is it runs if you put gas in the cylinder and it pops off, but won't stay running.
 

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Discussion Starter #6
Check to see if the fuel pick up fell off in the tank. I have seen many sleds get sold or parted out because it won't get gas, and won't run, and it's the fuel pick up that sends the gas from the tank to the fuel pump. The clue is it runs if you put gas in the cylinder and it pops off, but won't stay running.
But if the carb is getting gas it should be good, right? With every pull of the cord a significant amount of gas sprays out of the line. The carb fills very quickly.
 

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Can you keep it running on a spray bottle through the carburetor after you pour some in the holes? I wonder if something could be in the base causing a blockage. Rag, mouse nest....anything is possible. Bad crank seal maybe? Maybe it pulls enough vacuum to run the pump but not pull it to cylinder. Sounds unlikely once I get it typed...
 

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Discussion Starter #8
Can you keep it running on a spray bottle through the carburetor after you pour some in the holes? I wonder if something could be in the base causing a blockage. Rag, mouse nest....anything is possible. Bad crank seal maybe? Maybe it pulls enough vacuum to run the pump but not pull it to cylinder. Sounds unlikely once I get it typed...
By in the base do you mean in the crank case? I considered that also, but it runs if i dump some in the plugs. And I know, ive been running these same potentials through my head...seems so unlikely that it has enough draw to fill the carb quickly but not get it to the cylinder.
 

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how old is all the fuel ?
 

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By in the base do you mean in the crank case? I considered that also, but it runs if i dump some in the plugs. And I know, ive been running these same potentials through my head...seems so unlikely that it has enough draw to fill the carb quickly but not get it to the cylinder.
Yes I meant the crank case. By pouring gas into the cylinder, your eliminating the need for the fuel to travel through the base. Try a throw away spray bottle with some gas in it. Remove the airbox, spray some gas into carb inlet. Try starting it. Once it fires keep a spray going into the carbs and see if it will stay running. This should at least tell you what side of the carb the problem lies on.
 

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When an engine runs on fuel placed into the combustion chamber, you've eliminated most of the induction process. Any engine that has sat for a long time without certain things done to protect it for long term storage will lose pumping effectiveness. Just because it fires, doesn't mean it's flowing air as it should. Rodents will build nests in the exhaust and intake, urinate/defecate in these same spots. Also store nuts, and other food in particular areas.
1. Check cranking compression. 120+ is good.
2. Check for air leaks at crank seals, carb boots, etc.
3. Pull exhaust/muffler and check for nests, nuts, etc.
4. Make sure chokes are functioning.:bc:
5. Check for damaged reeds.
6. Look for broken piston skirts.

If compression is low, pour a little 2-stroke oil into each plug hole, reinstall plugs, and see if it temporarily raises compression enough to draw air/fuel from carbs. If rings were stuck, the running heat will often free them up.:bc:
 

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Won’t pull vacuumed , crank seals , check , had this problem in the way back time ago. , first cases ever had to split , check pu in tank first , good luck
 

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Discussion Starter #15
So i took the advice and poured a little gas in the carb inlet. It fires up, and then runs at like 3000-3500rpms and continues revving up until it runs out of fuel, irregardless of my adjusting the throttle cable tension or idle screw. When i hit the throttle, it died. Seems like a clear air leak somewhere.
 

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This engine should run on just a full choke when cold. Shouldn't matter if pilots are plugged. Is choke functioning?

I'm thinking that something else is the problem.

How about float bowl vent hoses? Are they kinked or plugged? Plugged vents prevents atmospheric pressure from entering the float bowls and applying pressure to the surface of the fuel to force it up the jets during the cranking phase. .

If not, then poor engine suction may be the issue.
The engine is an air pump. Anything that reduces suction can be the cause. Compression, reeds, air leaks, piston skirts broken, plugged exhaust, etc.

A carb needs a very rich mixture when starting cold.
Poor air flow won't draw hard enough to siphon fuel from the float bowl. But spraying fuel into carb mouth partially bypasses this requirement.

You must perform basic checks to eliminate possible issues one by one.:bc:
 

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Discussion Starter #18
Well y'all, the final answer: stuck ring (i think). After manually spraying gas into the carb three times, i realized it was running longer and longer with each time i did it. I took that to mean something was freeing up slowly. Added gas a fourth time, got her going, and just gave 'er for a solid five minutes. Gas drew in, i set the idle, boom good to go. Im assuming the heat busted it free as was mentioned earlier here, allowing for proper suction. All is well, the thing rips. Set for winter! Thanks for the help everyone :thumbsup:
 
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