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Discussion Starter · #1 ·
I bought a 99 EXT 550 EFI last week and we got some snow yesterday. It ran great for about 20 minutes and then it just sort of died. It still starts but has no power (might be in limp mode). While running with the hood up I noticed it back fire out the Carb boot. So I towed it home (lucky my freind was with me). Basically what I noticed was the Carb boot ( or EFI boot) had a big crack along it. The spark plugs were burning very lean. So my question(s) are. Could it be the crack in the boot that is causing it to run with no power or something else that caused the boot to crack? Also, the boot looks fairly easy to replace so is it something I should do myself. I'm fairly familiar with working on engines but since the efi has to removed I was not sure I should try it. If you guys feel pretty confident the boot is the problem I will change just them. If your not sure I'll have to have it completely looked at. So any advise would be great.

They are all cool but CATS rule!
 

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<BLOCKQUOTE id=quote><font size=1 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>Originally posted by rbig18:
I bought a 99 EXT 550 EFI last week and we got some snow yesterday. It ran great for about 20 minutes and then it just sort of died. It still starts but has no power (might be in limp mode). While running with the hood up I noticed it back fire out the Carb boot. So I towed it home (lucky my freind was with me). Basically what I noticed was the Carb boot ( or EFI boot) had a big crack along it. The spark plugs were burning very lean. So my question(s) are. Could it be the crack in the boot that is causing it to run with no power or something else that caused the boot to crack? Also, the boot looks fairly easy to replace so is it something I should do myself. I'm fairly familiar with working on engines but since the efi has to removed I was not sure I should try it. If you guys feel pretty confident the boot is the problem I will change just them. If your not sure I'll have to have it completely looked at. So any advise would be great.

They are all cool but CATS rule!
[/quote]
 

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I am not sure what boot you are talking about but if it caused the engine to run
lean I would be checking the compression . 20 min. is enough time to burn a piston .

Willson
 

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Discussion Starter · #4 ·
CORRECTION--It is a 1993 EXT 550

They are all cool but CATS rule!
 

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There are a number of things that can cuase this problem but lets look at the easy ones first. Check the compression. If OKmove on. The fuel pump must cycle and put out the corect volume of fuel to create the pressure. The pressure is regulated by the fuel regulator that has a spring in it that will tire over time. Your dealer will be able to tell you the pressure required. Check this. Also at the start of the season those electric pumps may not want to cycle, and a couple of taps with the old wrench will get them moving. This also has worked on a stuck injector after a two year rest. The injector was easy to id by just starting up the sled cold and feeling the exhaust Y. This is a start.
 

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Hope you didn't burn it up being to lean. Like everyone said check the compression, If the boats are cracked change them. This may sound stupid but make sure you have a good battery, the older efi sleds need a good one or they will just quit. It happened to someone I know last year on a 1994 700 efi. He had to be towed home, replaced the battery, and its been running great since.
 

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Definately replace that boot!!! Keep watching your plug color, so you don't melt a piston.
 

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Discussion Starter · #8 ·
Thanks for all who replied. I am checking the compression tonight. If it is good I will just replace the boots and have the dealer check everything out. Another quick question for you. If the piston or rings are done. Would you recommend having both cylinders/pistons replaced or just the bad one?
 

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If the other one is good, you don't NEED to replace it............buuuuuuuut if it were me, and you can afford to shell out the additional $40 or so for the other piston kit, I'd replace it as well. Nothing like the knowledge of having all new pistons and rings. IMO.
 

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Don't quote me on this since I am not a real Cat man, but it seems to me that in 93, the ext had nicasil pots. If so, and if you are low on a cylinder, you will probably have to replace the jug as well. I know a fellow who got his sleeved, but I am not sure that is the right way to handle that. Those pots were finicky.
 

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Discussion Starter · #11 ·
The good news is both cylinders tested at 120 PSI so I don't think I did any damage. I'll take it to the dealer and see what they say the cause is.
 
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