Carb rebuild to cure hard start

[bowler]

I'm contemplating winter jobs in my 96 Maxum 1750 w/merc 3.0lx and aplha 1 gen 2. As well as a general service/winterise I'm thinking about rebuilding the carb.

During the season the engine ran well, one issue was that it was hard to start when warm. It would start immediately if retstarted rightaway, if left for a few mins full throttle was needed to get it started. This approach always worked so I thought I'd wait until the winter and sort it then. It's now winter...

Should I rebuild the carb or might adjusting the float level help if the engine is flooding when warm? I've also heard that 'heatsoak' may be at fault.

Any advice folks?

 

[Don S]

Re: Carb rebuild to cure hard start

Before you go taking it apart, make sure it's not just the choke closing a few minutes after you shut it off.
With the choke closed, it will be hard to start because the choke will flood the engine. Full throttle will clear the flood condition and open the choke a little.

 

[bowler]

Re: Carb rebuild to cure hard start

Cheers Don,

I had a look today before winterising. Removed the flame arrestor and started it up, choke didn't seem to be doing very much at all, even when cold. I looked more closely and the idle mixture needle was really loose, virtually no contact with the idle cam. Gave it a little tweek and everything smoothed out (it had been idling a bit rough as well towards the end of the season).

Anyways, changed the fuel and oil filters and changed the oil. Fired it up and it went first time. Let it come up to temp, killed it and waited for about 5 mins and it started again first time. No throttle required and no signs of flooding. Hopefully this is the warm starting issue solved, sadly it'll be a while before she's on the water to see for sure. Completed winterising and left happy...

Sometimes I wish I didn't have to drive 60 miles to see the boat! It makes it that bit tougher to check and keep an eye on things.

Feel free to chime in if what I'm saying sounds off! Learning curve and all that.

D.

 

[PitchFork]

Re: Carb rebuild to cure hard start

From what I have read and seen after a shutdown and letting it sit gas dribbles through the primaries and floods the engine. It does not happen everytime but a good deal of the time. From what I have read and been told this is a problem inherit with carbs.

I wish their was a permanent fix to it. My first carb did not have this problem and started less than a second.

 

[cr2k]

Re: Carb rebuild to cure hard start

On the flat upper part of the venturis that go in to the carb throat is a tiny hole on each side. If this hole becomes plugged the carb will siphon gas in to the carb from the bowl. Make sure these are clean and open, but DO NOT use a tip cleaner or anything that can change the size of the holes.

 

[PitchFork]

Re: Carb rebuild to cure hard start

Could someone post a picture of this hole and how to clean it out? Could Compressed air be used?

 

[bowler]

Re: Carb rebuild to cure hard start

That would be great. I take it you are having the same problem pitchfork?

D.

 

[PitchFork]

Re: Carb rebuild to cure hard start

That would be great. I take it you are having the same problem pitchfork?

D.

Sure do along with a bogging problem going into the secondaries. I am going to rebuild my old carb but I need to make sure its a marine carb first 1705-9288 Rochester 4bbl.