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Still chasing down performance issues on 3.0lx carb guidance requested

D

douglasnc

Contributing Member
I'm wondering if maybe this re-built carb I bought online(from a marine carb site) could have came with the wrong jets installed. And if so could that be causing engine to seem to bog or stumble passed mid throttle? All recommended checks of other causes have been done, and seemed fine. Finally tore into this carb ,and found trash and mineral deposits all over the venturi cluster. Soaked and cleaned all parts as recommended here and re-assembled .Didn't think to check the jet and power valve size, but afterwards noticed in this SOLOC manual that sizes of jets varied depending on engine size Mercarb was being used on.Will go back in an check this out.My manual calls for 1.65mm jets and 0.84mm power valve.This dirty carb throws me because fuel system was clean everywhere else. Separator and both filters were clear of trash and water. Problem still there, and all new tune up parts and re-checked timing. Thanks for any insight here.
 
douglasnc said:
I'm wondering if maybe this re-built carb I bought online(from a marine carb site) could have came with the wrong jets installed. And if so could that be causing engine to seem to bog or stumble passed mid throttle? All recommended checks of other causes have been done, and seemed fine. Finally tore into this carb ,and found trash and mineral deposits all over the venturi cluster. Soaked and cleaned all parts as recommended here and re-assembled .Didn't think to check the jet and power valve size, but afterwards noticed in this SOLOC manual that sizes of jets varied depending on engine size Mercarb was being used on.Will go back in an check this out.My manual calls for 1.65mm jets and 0.84mm power valve.This dirty carb throws me because fuel system was clean everywhere else. Separator and both filters were clear of trash and water. Problem still there, and all new tune up parts and re-checked timing. Thanks for any insight here.
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While you were in there, did you thoroughly clean the main jets and power valve? I alway run torch tip cleaners thru the mains to ensure they are full open. For me, the build up of crud in the jets due to ethanol fuel cannot be cleaned with carb cleaner....unlike the old days of varnish, which carb cleaners could handle. When installing the air horn, did you ensure you went straight down with the power valve actuator? It is easy to miss the power valve pin if not. Partially clogged main jets and power valve will certainly cause a bog.
 
Will check all those things out as I go back together. Thanks. Noticed also today that power valve stem looks smaller than the old one from another Mercarb I had on. It isn't marked, but the other one is, and its a 0.74 which isn't correct for a 3.0LX at below 5000 feet. Calls for 0.845mm And the jets are 1.45mm for the older 2.5 and regular 3.0 engines.My manual calls for 1.65mm jets at below 5000 feet for the 30LX engine. Another thing was the power valve didn't have a seal under it. Lucky I had one. What's every ones thoughts on this? Could changing all these parts out for what the manual calls for cure my problem, or not? Not happy with company I bought this carb from..Also need tips on where I can buy jets as they aren't in the kits. Thanks again.
 
douglasnc said:
Will check all those things out as I go back together. Thanks. Noticed also today that power valve stem looks smaller than the old one from another Mercarb I had on. It isn't marked, but the other one is, and its a 0.74 which isn't correct for a 3.0LX at below 5000 feet. Calls for 0.845mm And the jets are 1.45mm for the older 2.5 and regular 3.0 engines.My manual calls for 1.65mm jets at below 5000 feet for the 30LX engine. Another thing was the power valve didn't have a seal under it. Lucky I had one. What's every ones thoughts on this? Could changing all these parts out for what the manual calls for cure my problem, or not? Not happy with company I bought this carb from..Also need tips on where I can buy jets as they aren't in the kits. Thanks again.
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Can't say it will for sure solve your problem, but jets and power valve that are way too small can certainly cause a bog....lean condition. Do you have spare jets?
 
No, Know A source? And I noticed that this manual explains differently how to set the float drop than say Mikes carb video's does. Tried it by this manual (SE LOC ) ad it leaked fuel into intake when trying to start engine.
 
If you don't have the correct Mercarb base gasket it will never idle work a darn...needs to be a thick one. I have one if you need it...just PM me and I'll stick it in the mail.
 
Hi Fastatv.Engine tag says #F067528 3.0LX. Carb number not checked yet, but after re-build kits get put in them,its anyone's guess as to what jets and power valve gets replaced. Other wise, there all the same aren't they? But setting up the float for needle type is important. The needle in this carb looks to be solid! I mean it doesn't come apart at all. Thought that was odd as I don't know for sure how to adjust the float level. Wasn't a gasket under the power valve nor one of the jets. And no baffle around needle valve. Wrong jets and power valve size. Too small. Not happy paying over $300.00 from a well known marine re-builder. Will put a kit in it I guess,and try to find some 1.60 or 1.65mm jets and proper power valve. Thanks again, and thank you too guyjg for the offer,but wll make sure kit has the thick gasket. Nice people here, and I appreciate you all.
 
Doug, not sure that jets will come with your kit unless your able to purchase what was called ( or used to be called ) a master rebuild kit. Anyway, have you contacted the seller of the carb? Maybe he will provide you the required jets and power valve...or exchange with you. Your manual should cover the float adjustment, the measurement from toe of float to carb body ( gasket mounted ), best guess is either 10 or 14 mm. The 10 mm is for the solid type valve, the 14 mm is for the spring loaded needle valve but, certainly go by what the manual indicates. Keep us up to date...hope you get it figured out and get on the lake and have some fun! :)
 
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