mercarb 2 bbl float setting?

[CHEVYJEFF]

My 1997 mercruiser 5.7 260 hp is hard to start after running at steady rpm for periods of time like sking or cruising. If I turn it off it will start right back up but if it sites for 10 min its acting like its flooded. I know this because I can push the throttle up ¼ way and it will start. I rebuilt the mercarb 2 barrel over the weekend. Followed the float settings to the millimeter as specified in the instructions. Launched the boat and as it was running I could see gas pouring into the engine. Obviously the float setting was way off. So a quick adjustment w/ a pair of pliers on the float at the boat ramp it was running fine. But I still get the hard start after sitting. It is like the carb is leaking down. Are there any other specs for the float in this carb. It wasn’t running lean after my adjustment and has good power but would like to solve the leakdown problem as its why I rebuilt it in the first place.

 

[tommays]

Re: mercarb 2 bbl float setting?

if it starts at 1/4 everytime it sounds normal a carb motor usally wont start with no throtel at all<br /><br />we have all been spoiled by EFI cars<br /><br />have to see what others think i would go through the carb settings again and see if you can find out were you went worng with the float setting<br /><br />tommays

 

[wake5150]

Re: mercarb 2 bbl float setting?

Out of curiousity what did you initially set the Float Level to? I'm assuming solid needle with no spring? I'm guessing somewhere around 12mm to the center dot?<br /><br />Float drop was probably somewhere near 45mm? <br /><br />What do you think your subsequent setting of the float level was?

 

[CHEVYJEFF]

Re: mercarb 2 bbl float setting?

I used the needle & seat w/ the spring and rod because thats what type was in there to begin with. Was that wrong? because i saw the other little solid part that would go in theplace of the spring, but the exploded view showed the spring and rod. Ill have verify my dimension settings tonight when i get home as I left the stupid instructions on the counter. and im here at work..doh.

 

[Don S]

Re: mercarb 2 bbl float setting?

If I turn it off it will start right back up but if it sites for 10 min its acting like its flooded. I know this because I can push the throttle up ¼ way and it will start.

That sounds quite normal to me. It's not flooded, when you raise the throttle, the accelerator pump squirts some fuel into the engine and it starts.<br /><br />Like stated previously, it won't start like an EFI engine.<br />Here are the specs for the carb.<br /><br />

 

[CHEVYJEFF]

Re: mercarb 2 bbl float setting?

Cool...Yea im spolied w/ my f.i. on my truck so i guess its just the nature of the beast to start w/ partial throttle. I can live w/ that. Now just got to get the adimral (wife) to get used to it. Where did that chart come from? I noticed some diffrences from the one posted and the one that came w/ the sierra carb kit.

 

[Don S]

Re: mercarb 2 bbl float setting?

It came from the Mercruiser service manual. There is a complete section on rebuilding the Mercarb.