ECU What??

[Hottrucks]

Ok guys Help me out again?? I looking at a boat with EFI motors on it and I know SH*T about ECU's. What I do know is the motors are 1990ish BP's and have a fresh rebuild on them, I have been told they have A-40 ECU's on them.

Keep in mind I don't want to gernade these things before I can afford to repower it in a year or so. I don't need top end of them either I just want them to make good power and live :cool: till I can get the rest of the boat the way I want it.

Heres some Questions that Might help me understand ???

1) What are the different ECU models?
2) Which are Digital?
3) Why are digital better and Why?
4) Is it worth the change ( I have heard $500 each)?
5) Is it Something I can do myself?
6) What should I beware of with these EFI motors
7) Will I need to tune these things?

Ps Don't ask what kind of boat, I'll be telling ya all soon as I can close the deal :cool: All I can say is it'll be nice to see triple digits after some over due seat time!!

Thanx
Jeff

[YELLOWSS]

the a-40 is the latest merc ecu box for the b/p. it is digital and it is a great box.
the older analog box's are a-7 a-13. the a-40 should work great if the motors are stock. when you run a digital box you have to run a resistor plug. not much tuning if they are stock motors. i would recomend egt's. if you don't spin them high rpms they should last a long time.
roy

[Hottrucks]

ok I'm going to try to stay civil with the Rpm But I'm sure I'll bump the once in a while. The boat has EGT gauges in it what would be accepable #'s on them? and when should I worry?

Also How can I tell one box from the other if you havn't figured it out yet I don't have the boat in front of me.I just trying to learn all I can about them first so when I take the cowl off I can stare at it until it runs better kinda like the new cars??

Thanx
Jeff

[YELLOWSS]

egt's when it goes over 1200 you need to keep your eye on it some say max 1225 some say 1250. the rev limiter could be set at any rpm's. the guy your buying it from should no. on the back of the ecu there are numbers they should say a-40. are the egt's for both sides of the motor or just one side? both side are better and digital reading is the way to go not a needle with numbers like 6,7,8,9. who can reed those things in rough water running 80 - 100 mph. i would run fuel pressure gauges too.
good luck
roy

[Hottrucks]

Thanx from what I remember it's dual swing gauges (both sides both engines) 1200 is about what I like to see my diesal running also??
How is the rev limiter set?

[YELLOWSS]

it is inside the ecu. you have to send it out to rapair to have it changed.
roy