Jump to content
Sign in to follow this  
716Stella

Merc 350 mag Surging/Popping @2800/3000 rpms

Recommended Posts

Hello. I have have a 1988 chaparral 2350 sx. With a new mercruiser 350 mag with 10-20 hrs on it.  Starts fine, idles smooth.  Engine sounds fantastic at idle. In and out of water.   But after shes under load in the water will start to surge. She will drop rpms then jump. Then drop,  I have to back off the throttle to keep from stalling, as soon as i back off engine runs smooth.  When this problem starts though, the engine will pop a bit as well. At about 2800 rpms, just as she starts to plane out.  This happens intermittently.   Bought the boat this year.  Put in about 150bux worth of fresh 91 ethanol free fuel in it.   This is the 3 rd time so far that this has happened. I changed the F/W seperator, and no relief.   However after running for a while the problem will go away and she will run fine   Then it comes back.   Any suggestions will be greatly appreciated

 

 

Share this post


Link to post
Share on other sites
1 hour ago, Jjlai724 said:

Change the cap and rotor.

You dont think its fuel related?   Bc it doesn’t stall out, nor does it idle rough.     

Share this post


Link to post
Share on other sites

I would change the cap and rotor if it hasn't been changed when the new motor was put in.  Or at least take the cap off and see how it looks inside.  Any arching marks or burnt marks.  

If it still happens afterwards, then maybe get the fuel pump checked. 

Share this post


Link to post
Share on other sites

Mine did this. Bad bearing in the distributor an the gear on the bottom of the distributor wore real quick.  Just take the cap off an make sure you don’t have a lot of up an down play or counter an clockwise play. The housing are plastic crap an cheap bearings 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×