Mercruiser fuel pump & Choke tubes

[fixit10101]

I'm working on my daughter's boat and finding problems. 1977 Starcraft, 140 Mercruiser I/O. The fuel pump vent line at bottom of fuel pump(connected with steel & plastic line) is plugged with a screw. Where is this line supposed to connect to? Nothing in the Mercruiser manual. I read a post here (http://www.outboardrepairs.com/topics/009109.html) says it goes to carb; but where?

Also the tube from the choke was dangling loose (rusted off). In addition, the threaded fitting on the choke housing seems to be metric thread(measures 1.00 with metric pitch gage) but the O.D. of the threads measures .440", which does not match with a metric thread size. Someone had cross-threaded a 1/8-27 flare nut on it and buggered up the first couple threads. I can fix the threads with a triangular file. Where is this tube supposed to go? Is this choke tube available from a Mercruiser dealer? Or can I adapt a steel brake line using 1/8-27 NPT fittings?

I've included 2 pics. One shows the fuel pump line. The other is the carb. There's a brass plug at base of carb, and to left in pic on manifold is another plug. I'm assuming these are where the choke and pump lines go. Am I correct? And, if so, which goes where? Thanks in advance. Jim

 

[DUBKAPKE]

Re: Mercruiser fuel pump & Choke tubes

I have an '82 140 I/O which should be the same as yours. My serial number is 606...... and I believe it is in '77-'82 group. The thermostatic choke tube should go to a tube in the exhaust manifold. It just fits into the tube coming out of the manifold. The Mercrusier part number for the tube from the carb is 32-53371 and the fabric insulating cover that goes over the tube is 32-53404The tube that goes into the exhaust manifold is 32-53370. You can get the tube from the carb 32-53371 from marine power service for $8.00 but they do not have the cover 32-53404. I just replaced my exhaust manifold and the new one did not come with the tube 32-53370 but I was able to find a new one on Ebay for $27.00.

The other rubber tube from the fuel pump does go to the carb but I cannot recall to where. I will take some pics tonight and post them.

Hope this helps.