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Fuel question for the OMC techs
#8887964
05/02/13 02:04 AM
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Joined: Jun 2006
Posts: 9,805
Yellowcat
OP
TFF Celebrity
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OP
TFF Celebrity
Joined: Jun 2006
Posts: 9,805 |
I have a 1977 evinrude 9.9. I bought it dirt cheap knowing it had spark and compression. I got it running with no problems at all. But it will not run wot in gear.
I am good friends with the best omc technician in the area. We looked at it today and its running too rich at wot. Fuel pump is good, carb is good. I can give ya more details if ya want. We checked ignition. Swapped coils and powerpack.
So its running too rich at wot. What could cause this? I am open to any suggestions.
Justin 63lb, 2 58lb, several 40's, 38lb, and several 20lb yellas.
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Re: Fuel question for the OMC techs
[Re: Yellowcat]
#8888721
05/02/13 11:29 AM
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Joined: Sep 2008
Posts: 111,385
hopalong
Pescador Loco
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Pescador Loco
Joined: Sep 2008
Posts: 111,385 |
float out of adjustment or sticking. choke sticking shut. look at # 3 and 9 on this diagram, either could be sticking and causing it. try running a can of seafoam in a gal of fuel mix and run it both wide open and idle, run it for a while then shut off and let sit for a couple of hrs then run again. do this in the lake if possible. 
Last edited by hopalong; 05/02/13 11:30 AM.
" Hop, set the hook"! hopalong 99,999 TexDawg 99,999 FJB! not my president by a long shot!
lake fork FISHERMANS COVE MARINA/reservations - 903 474 7479
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Re: Fuel question for the OMC techs
[Re: Yellowcat]
#8888854
05/02/13 12:36 PM
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Joined: Jun 2006
Posts: 9,805
Yellowcat
OP
TFF Celebrity
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OP
TFF Celebrity
Joined: Jun 2006
Posts: 9,805 |
Hopalong, everything you mentioned is good. We are pretty much positive its not carb related or fuel pump related. Unless someone changed the orifice out to try to make it a 15 and didnt know what they were doing. The orifice in it is a 38. We are pretty sure the 38 is for a 9.9 and a 58 is for a 15. Does anyone know this for sure? With it not being carb related, fuel pump or ignition. Could it be reeds?
Btw i got 90 psi both cylinders
Justin 63lb, 2 58lb, several 40's, 38lb, and several 20lb yellas.
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Re: Fuel question for the OMC techs
[Re: Yellowcat]
#8888903
05/02/13 12:52 PM
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Joined: Sep 2008
Posts: 111,385
hopalong
Pescador Loco
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Pescador Loco
Joined: Sep 2008
Posts: 111,385 |
can you rev it up in neutral? if your sure the butterflies are working right then got to spark, may be that your dropping spark on higher rpm's, check timing @ wot.
" Hop, set the hook"! hopalong 99,999 TexDawg 99,999 FJB! not my president by a long shot!
lake fork FISHERMANS COVE MARINA/reservations - 903 474 7479
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Re: Fuel question for the OMC techs
[Re: Yellowcat]
#8889445
05/02/13 02:42 PM
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Joined: Jan 2003
Posts: 825
waydon1
Pro Angler
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Pro Angler
Joined: Jan 2003
Posts: 825 |
Yellowcat, 90 psi is borderline compression on that engine.. Try a differant gauge and/or do a decarb and test again.. A leakdown test will tell you a lot more about the condition of the cylinders than a comp test... Make sure the timer base is advancing all the way... Check WOT timing... Most of the time a reed problem will cause the engine to spit gas back out of the carb throat... Do a search on leakdown test to understand it... A factory OMC service book is a big help....The after market books can be wrong on some things....
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Re: Fuel question for the OMC techs
[Re: Yellowcat]
#8891115
05/02/13 08:25 PM
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Joined: Jun 2006
Posts: 9,805
Yellowcat
OP
TFF Celebrity
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OP
TFF Celebrity
Joined: Jun 2006
Posts: 9,805 |
Hopalong it will rev up until the timing plate hits the stop in neutral but it does not seem like it is reving up as high as it should. I know it will only reach a certain rpm because of the stop that is a safety for neutral. Checked coils powerack kv voltage timing at the spot where it falls on its face. All good. In the omc service manual it says for a bad reed it would backfire. Mine does not backfire though. Will check out a leakdown test
I know the guy that is helpin me with it WIll figure it out. Hes been workin on omc for 30 plus years and has never had one like this before
Thanks for all they help and suggestions. My ears are still open!
Last edited by Yellowcat; 05/02/13 08:26 PM.
Justin 63lb, 2 58lb, several 40's, 38lb, and several 20lb yellas.
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