Help with mariner 2.4l 175 efi

[Partonjoshua]

Checked the purple wire from the key switch all the way to the ecu it was not hot until I turned the key on. There is a red wire running from the starter solenoid to the cannon plug for the ecu and it is hot all the time. Is this normal?

 

[Dukedog]

sounds like tha pump driver circuit in tha ecu may be toast... try this. disconnect both pos and neg wires on tha pump and tape 'em off.. install a plain ole ground from any motor ground to tha neg. side of tha pump... now install a wire from pos on tha pump to tha purple that should be ona small plastic term block on tha starboard side where all tha 'lectrics are located... this will control tha pump with tha key only.. should go on and off with tha key... if pump works as it should then tha ecu driver is bad....

 

[Partonjoshua]

I'll try that in the morning.

 

[Dukedog]

if it works then other grounds in tha ecu could be messed up which could be tha cause of your problems.. that driver circuit usually just effects tha pump but it could possibly cause any number of problems with grounds for other circuits in tha ecu....never seen it before but that don't mean nothin'......

 

[Partonjoshua]

OK wired the pump the way you said and it now only runs with the key switch on.

 

[Dukedog]

run it... see if anything has changed....

 

[Partonjoshua]

Took the boat out this morning to test, still will not get on plane. Checked spark while it was bogging and have spark on all 6. At wot while it is bogging if I do a quick squirt of fuel directly into the throttle body it begins to pick up rpms and will throw you back so I'm pretty sure it's a fuel delivery problem. Thinking about ditching efi and throwing carbs on this thing, will the horizontal 5 petal Reed plate mount to my block, I ordered the Reed plate gasket for a carbed 2.4 to use as a template to see if bolts match, what do you think? Carbs I know but efi is a whole new world to me.

 

[Dukedog]

check tha mechanical pump... it can be replaced with a small, low pressure, inline 'lectric pump for less than 50 bucks...it will also eliminate tha "pump it up bulb".. tha change ta carbs is simple.. other than a carb reed plate all you will need is tha throttle cam, rod, air box (200 carb stuff) for for tha carbs..

is your motor a "fat block 2.4"... its right in that time period of tha block change.....

 

[Partonjoshua]

How can you tell if it is a fat block

 

[Dukedog]

hard ta tell for tha not knowing.. it will be a "2.5" style block with 2.4 sleeves.. do tha heads have alignment dowel pins? is tha exhaust divider plate one piece or two (one stacked on top of tha other)?

 

[Partonjoshua]

No Title

Attached a screenshot of the divider plate for my serial number looks like 2 pieces but not sure, never had the heads off, but the diagram for the heads do not show dowel pins.

 

[Partonjoshua]

Found my problem, with the motor running like crap. Pulled my Reed plate to see if a carbed Reed plate would mount to it and found that #6 and #3 ate 3 stainless reeds. Those 2 pistons are toast but the sleeves look alright. Motor still had good compression which threw me off. Is it possible to hone and re-ring with sleeves installed, not sure what the sleeve is made out of but it looks like it had a recent rebuild w/ .30 over pistons.

 

[Dukedog]

all six sleeved and 30 over?

 

[Partonjoshua]

Yes

 

[Dukedog]

not good!

 

[Partonjoshua]

Should I cut my loses and part it out?

 

[Dukedog]

me? yes but its your choice... don't know very many folks that will build a 30 over efi ta start with... especially tha early ones..... if ya look you'll see tha merc doesn't offer anything bigger than 15 on their efi's.....

 

[Partonjoshua]

Alright that's all I needed to know thanks for your help.