MARINER 225 POWER TRIM CUTS RPM

[ROUGE]

HELP. I have a 1999 mariner 225 offshore efi. When cruising at top speed if I adjust trim rpms drop to almost nil. Mechanic has had it a month and can't solve it . Checked out stator, alternator and all grounds . At low rpms drop is less notable but still detectable . Get this . mechanic installed non functioning alternator and problem went away !!! Any suggestions?

 

[The Marine Doctor]

Re: MARINER 225 POWER TRIM CUTS RPM

EFI and DFI engines will have that type of a problem if you are using a battery that is too low in amps.<br /><br />Are you using a 1000 CCA battery?<br /><br />TMD

 

[BW23]

Re: MARINER 225 POWER TRIM CUTS RPM

Hey DR , <br /><br />I have a 97 MERC 225 EFI and have been having intermittent spark plug fouling and intermittent CDM operation. <br />I installed 2 new size 27 Stowaway deep cycle batteries this past spring. Do you think these batts. (deep cycle type) might be causing my problems ??<br /><br />Thoughts please.<br /><br />previous post.<br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=29;t=009216

 

[The Marine Doctor]

Re: MARINER 225 POWER TRIM CUTS RPM

It is possible. Your manual that came with your engine should tell you the proper size batteries that you should be using.<br /><br />The problem will get worse and worse...until the ECM just turns the engine off.<br /><br />TMD

 

[Hasbeen]

Re: MARINER 225 POWER TRIM CUTS RPM

When I was just a kid and had my first car there was this older mechanic fellow that I took it to to teach me how to tune it up! The very first thing that he did was clean the battery cables and check the ground! I ask him why he was doing that as all I wanted was a tune up! He laughed and said "son, If you do not have enogh voltage and proper grounding you can tune all you want and it will do no good"! I learned right then that voltage and grounding was important!<br /><br />Just me jabbering!!<br /><br />Hasbeen

 

[ROUGE]

Re: MARINER 225 POWER TRIM CUTS RPM

Thanks for the advice ,Doc. I don't have 1000 cca but I do have a brand new 800 cca batt. Shouldn't this be enough . Mechanic now attempting to check the ecu . Think this could be it ?