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Very confused

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freddie1944

Member
Hi, is there a way to tell if the carb. on my boat motor is the correct one. I can't get it to run right and I am starting to think. That the motor and carb. are two different years. thank you.
 
What is your motor doing / not doing ?-------The orifice plug is the fixed high speed jet.----What hp motor and year ?
 
It is a 1969 18 horse Evinrude. I bought it about two months ago. It will start idle and run slow. But when I give it throttle it dies out. If I get it back to idle quick enough. It will continue to run. If I don't and it quits. All I have to do is hit the starter button and it starts right away. I have many new parts in the motor. So I can't just give up now. When I put it in a barrel at home it will run up full R.P.M. s I really really want to keep this motor. It has electric start and I am too old to pull the rope. Everything appears to work well in the barrel. But put it in the lake and it dies at the exact same RPM every time. I have to much invested to quit. I am also sure it is just some weird thing. The carb has been cleaned three times. It has new plugs, wires, coils, points, condensers gas lines. I have tried a different tank and no squeeze bulb at all. I have pumped the bulb when it wants to quit. But it makes no difference. I am at a loss and don't know what else to try. Any ideas will be very much appreciated.
 
Compression test done ?-------Does spark jump a gap of 1/4" on both leads , yes or no.----------Does opening the low speed needle help ??----Yes the low speed mixture has a huge affect on acceleration.---------Is throttle plate opening too soon and have you adjusted that ?
 
First of all. Thank you for putting some thought into this. Compression is 105 top and bottom. Opening the low speed needle does not help. The timing has been adjusted all over the place. The carb is starting to open when the roller gets between the two marks. Model number is 18902d The picture from Serra on a 1969 does not show the high speed tube in the middle. The 1968 does show the tube. My carb does have the tube. That is why I wonder if someone put a 1968 carb. on a 1969 motor. And that is why it does not run at full throttle in the lake.??????????? Oh, and yes it does have good spark. Thank you again for the help I will try any thing that you suggest.
 
Have you checked the reed valves ?-----The motor will run equally well with a 68 or 69 carburetor !
 
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I took it to a boat mechanic. He said the reeds were fine. I wish I could put the break down on here from Sierra. The carbs look very different between a 1968 and 1969. The inside of the bowl shows a high speed tube and gasket in the 1968 But none in the 1969. My 69 has the tube and the mechanic put in a gasket. It did not have one. I don't know if I should buy a kit for a 69 or a 68.
thank you for the help.
 
O.K. I just got it straightened out. 68 and 69 carbs. are completely different. After much discussion with a parts man. We ended up matching up the float gasket.It matches up with 1969. I also found out, that there is no gasket under the needle seat in my carb. I am hoping that, The lack of a gasket is what Is causing the stalling problem when I give it throttle. Could that be the problem.?
I would also like to thank all of you. Who helped me with ideas. I appreciate it very much.
 
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