Odd problem with Mercruiser 3.0L

[ezjam]

Re: Odd problem with Mercruiser 3.0L

http://www.boatfix.com/merc/Servmanl/13/13covr2.pdf

Don, I followed the specs on the manual to the T. Float height is set at 9/16th and 1 3/32 as per manual.

However, now I'm not getting enough gas in the carb. Starts right up every single time... but when I gun it, it lags and hesitates. Only way to get it to high RPM's, is to slowly give it gas. Unfortunately I have a boating trip this weekend and I have to have it running by tomorrow (Friday.) So I'm in a bit of a bind now. Prior to attempting to adjust the height, with carb upside down, the float height was set to a couple of mm. Does not sound right but that is the position where it is working the best.

Any recommendations?

ez

 

[Don S]

Re: Odd problem with Mercruiser 3.0L

Is the accelerator pump working properly?
Is the idle mixture adjusted properly with the engine running. No, the mixture is not adjusted if you set the screw out the proper number of turns. That is just a starting point.
Carb and ignition must all work together for it to work properly.

 

[ezjam]

Re: Odd problem with Mercruiser 3.0L

Hi Don,

Accelerator pump... good point. I'm going to check that out next... Here's what I intend to do... Let me know if there is a better way to test it.

I am going to have someone give it gas while I look inside the carb to see if gas is being sprayed.

How's this for a test plan..

Throttle position from
0% (neutral) to 50% then back to
25% and push to 75% then back to
50% and push to 100%

In theory it should spray the entire time... yes?

Is the accelerator pump working properly?
Is the idle mixture adjusted properly with the engine running. No, the mixture is not adjusted if you set the screw out the proper number of turns. That is just a starting point.
Carb and ignition must all work together for it to work properly.

 

[ezjam]

Re: Odd problem with Mercruiser 3.0L

To Don and all who helped.

Thanx guys! As of now, it looks like I won!

1. Timing was off, so I adjusted it as per EST specs.
2. Idle was too high, so it was dieseling. Now it dies right away.
3. Mixture was good. But I checked anyway
4. Float was so off... way off.

Now it starts right up... revs on cue... stops when I ask it to.

This weekend should be the final test. I'll take my toolbox just in case.

ez

 

[Don S]

Re: Odd problem with Mercruiser 3.0L

1. Timing was off, so I adjusted it as per EST specs.

Hope you put it in Base Timing Mode before setting the timing, otherwise your timing is NOW way off and you could loose a head gasket or worse.

 

[ezjam]

Re: Odd problem with Mercruiser 3.0L

Hope you put it in Base Timing Mode before setting the timing, otherwise your timing is NOW way off and you could loose a head gasket or worse.

Sure did. Shorted the two white leads on the distributor cables and shorted the switch interrupt switch.

I will run again a few times before hitting the water just to be sure.

Thanx again.

ez