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Reverend Dennis
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786 Posts
Discussion Starter #1
Ok finally got the ext 580 efi going Again. Replaced the overbored pistons with a stock set of cyls and pistons off a another motor.

Compression on the motor that I bought was 120 before removing the cyls and pistons. It is now still 120 on my motor with them in it.

Started and ran fine last night. Ran it for about 30 mins or so. Rechecked the torque on the bolts and made sure no leaks anywhere. There were none.

Took it out today on the lake, about 6" of snow, slightly heavy packing snow. Ran great for about an hour. Then it would bog baddly at around 1'/2 throttle about 6k rpms and not get above 45mph

At one point it almost died completely, (remember its an efi) feathered the gas and it stayed running, but ride back to shop, was boggy around 30mph, with a lurch.

Took it out in front of the house for a clean out rip to see if it would speed up, ran like a raped ape, No issues, until I let off the gas to stop, slowed to a stop and as it idled down, it died, hard restart, replaced plugs with two new ones and it fired right up, brought her back in and it died again at idle.

Will restart fine, and idle fine, just after a run it will die out. Compression is still 120 on both, Fuel pressure is 35lbs on the gauge. The plugs come out slightly blk/bwn and a little moist.

Any ideas?
 

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Reverend Dennis
Joined
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786 Posts
Discussion Starter #3
That is my thought as well, Primary doesnt look dirty, Just cleaned it before rebuilding the top end the last time, only ran for 30 miles then had to rebuild it again.

The secondary may be sticking (again), plan and pulling it tomorrow and rechecking it.

Would that cause it to die out after a fast run?
 

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Reverend Dennis
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786 Posts
Discussion Starter #9
I was starting to think that, plan on bypassing it and seeing if that fixes it, I really hope so, have dumped to much $ into already
 

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Breaker of Balls
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313 Posts
my 800 started doing the same thing the other day, it would run fine for about a 1/4 mile then bog down and die and super hard to restart. we think it's got a bad coil, maybe thats your issue too.
 

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Reverend Dennis
Joined
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786 Posts
Discussion Starter #15
Ok unplugged the TSS. Seemed to fix it on first run. Went out hard and fast, came in and let off throttle. RPM's started to come down slow, then rapidly dropped to below 500, it brought itself back up.

Thought Ok Great!!!

Just took her out again to move it around to bring it in workshop, (have to work a little today) and she wanted to bog a little, and seemed to die down again.

Noticed when I parked her, that the engine was nice and warm, Hot even, but only the lower coolent line seemed warm, the top line going to top of the head was still cold. Also seemed like I could smell fuel.

Inspected all lines again and found no leaks.

Any ideas now? Going to re-clean clutches tonight when get a chance and see if that might be it, but visually they are clean as a whistle..
 

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Super Moderator
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17,904 Posts
You will need to get the coolant filler higher than the rear heat exchangers. If you have a trailer that tilts, run it up on the trailer and idle it with the cap off. Any air will migrate to the filler. Without a trailer, you will need to be creative. I have used milk crates under the skis to lift the front and then sat on the rear.
 

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Reverend Dennis
Joined
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786 Posts
Discussion Starter #19
Ok got it. Will use the make shift come along to lift the front higher then the back..

Thanks again!
 

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Reverend Dennis
Joined
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786 Posts
Discussion Starter #20 (Edited)
Ok burped the system I think. BUT noticed a plug not connected, it connects to the bottom of the fuel rail assm on the stator side. Havent took her out yet, but what does that plug/sensor do and would that have been my issue?

EDIT: Ok took her out, Man its cold out! Anyway, seems ok but now I have a 5k bog! If I stay on the throttle hard, it will engage and ripe, but if I hit it hard from the start, it engages at 4k and bogs till just after 5k then feather throttle and it will take off..
 
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