OK...Got it started but didn't last long. 1971 Merc 1350.

gidds

Seaman Apprentice
Joined
Jul 14, 2007
Messages
48
Boat has set for a while. Got it out. Starter works. Compression good and almost same in each cylinder. Fairly new plugs.

Tried to start and could not get it to run. Ended up changing the floats in each carb (top carb float was saturated, floats have never been changed). Checked bowl screens and everything looks OK. Had a crappy connection on fuel line at the tank end. Replaced and no fuel/air leaking. Checked fuel pumps and the appear to be in good condition.

Added seafoam to gas and oil mixture. I used high octane gas, but old oil (seemed to be OK, but I'll get new oil tomorrow).

Spent quite a while trying to start. Good pressure on bulb. Finally got it to start and rev up fast using warm start leaver, choke then release. Would rev up then stop.

Kept messing around and finally got it to crank using no warm start lever, choke the release. Very inconsistent. When it was running, I would have to keep squeezing bulb fir most of the time. It would run for a little while (20 second) and I could keep it running but hitting the choke for a second or two. Repeated it numerous times and had it running for a minute or so. Could even put it in gear and rev it up a little more, but nothing consistent.

What should I look at next??????
 

MH Hawker

Vice Admiral
Joined
Jul 13, 2011
Messages
5,516
Re: OK...Got it started but didn't last long. 1971 Merc 1350.

carb rebuild
 

gidds

Seaman Apprentice
Joined
Jul 14, 2007
Messages
48
Re: OK...Got it started but didn't last long. 1971 Merc 1350.

carb rebuild

Disassemble, clean then reassemble or get the rebuild kits (IE new needles, etc.) ?

Also, the previous owner stored the engine on its side while he replaced the transom of the boat. I used it for years, but it never has run to its full potential. Have had lots of work done but still never 100% (I know its an old engine, but it's in pretty good shape.

With that being said, I have always wondered if there is something blocking the ports behind the fuel pump gaskets. Its my understanding that exhaust pressure from the engine operates the gaskets. Could those passages be blocked and not sending goo pressure to the membrane....?

Thanks in advance.....
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,074
Re: OK...Got it started but didn't last long. 1971 Merc 1350.

Check the fuel pump(s). Sounds like something is not working. Maybe the 1 way valves are gummed up. Check primer bulb as well. Get new gasket sets and inlet needle to go with the new floats.
 

Yesterday

Petty Officer 1st Class
Joined
Feb 21, 2012
Messages
354
Re: OK...Got it started but didn't last long. 1971 Merc 1350.

Curiousity: Why replace the needles, Chris?
 

Mi duckdown

Commander
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Apr 14, 2007
Messages
2,575
Re: OK...Got it started but didn't last long. 1971 Merc 1350.

So you don't have to reopen the carbs and replace them. Once you have the carbs off, might as well replace everything.
 

gidds

Seaman Apprentice
Joined
Jul 14, 2007
Messages
48
Re: OK...Got it started but didn't last long. 1971 Merc 1350.

So you don't have to reopen the carbs and replace them. Once you have the carbs off, might as well replace everything.

MiDuckdown.....There is a repair kit and a rebuild kit.....the repair kit has a butt-load of parts (numerous needles, springs, float levers, etc).....the rebuild kit has the gaskets, inlet needle and seat, etc. Do I break down the entire carb, clean then reassemble with everything new (assumed to be the repair kit) or just the parts that are in the rebuild kit......

With that being said.....When I look at pictures of the repair kit, it has a primary float lever the has contours and bevels on the surface near the float spring contact. My old ones are flat as well as the ones shown in my old manual. Any idea why different?
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,074
Re: OK...Got it started but didn't last long. 1971 Merc 1350.

Yesterday, The inlet needles wear out and allow fuel to leak. Floats disolve or crack. Gaskets are usually replaced so they seal well.
 

Yesterday

Petty Officer 1st Class
Joined
Feb 21, 2012
Messages
354
Re: OK...Got it started but didn't last long. 1971 Merc 1350.

I wouldn't have thought of them wearing, but I guess they do spend a lot of their lives traveling...

Thanks.
 
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