I have a Merucry 200 EFI That has been hard to start since I have owned it (bought used about 4 years ago, power head was replaced and still under warranty when i bought it). The motor has to be cranked for quite a long time to get it to fire up and run. Lately, I run the battery down cranking on it. Put a charger on and crank away till it starts. Once started it runs fine. For the rest of the day it takes little more than a bump to be running. Air temp dont seem to matter. If I understand corretly, with EFI, there isn't really anything I can or should need to do as far as choking, giving it some throttle, etc. I just replaced the plugs and verified the battery is good (as per Autozone). Any ideas what to look at next?

Not sure what model you have but check your CCAs on the battery. I have been told that Optimax's like a 1000. When I replaced mine the biggest one I found locally was at O'Reillys

Efi motors rely on high pressure to inject the gas and oil mix into the piston. So battery strength is definitely a factor. Also, before it starts, there is a front fuel pump that feeds the high pressure pump. Make sure you turn the key to on position, and listen for the pre start pump to come on. If it does, them crank it over after 10 seconds. Of course, check your fuel filters and both fuel pumps too.

Good luck
Tim

Thanks Stump and Skunked! My CCA rating in the battery is 1000a. Not sure how the tester works at autozone but they punched in the CCAs and the meter returned that the battery is good. I have been reading that fuel presure at the injectors can cause the problem so I will look into getting a gauge to measure it. The Clymer manual says 34-36 PSIG. I am not really sure why it seems to crank ok after the initial startup. I will update when done....

When my high pressure fuel injector pump was going out, I took it apart, and there was rust flakes, and all sorts of inners of the pump that fell out of it. But it was over 10 yrs old. Once replaced, it was perfect again. Good luck, and post what you find.
Tim

what year? are ya pumpin' tha bulb till firm?

TLW, the year is kind of up in the air. The original motor was a 1995. They guy I bought it from said that it was replaced with a 2003 powerhead. The powerhead was installed by Extremem Marine in Grand Prairie. I have the paperwork but it does not specify the exact year model. From what I understood form the old owner, it was originally a Carb'd motor. I know there are a lot of diferent serial numbers and parts and changes alll the time on these engines, but it is a 2.5L EFi engine. and yes I pump the primer bulb till firm.

never have touched the primer bulb on my Optimax. Don't know why you need to with electric pumps.

UPDATE: Checked the fuel pressure to the injectors, just over 36 psig ( not 37...). I took a look at the voltaage at the TPS. Was .17. Supposed to be .20 to .30. Adjusted to .25. will stick it in the water tomorrow and see if that makes adifference. Seems pretty minimal for voltage but ....

Anyone know what effect a low voltage from the TPS would have from a cold start and why starts are easy after the initial hard start? Trying to make sence of all this.....

up till '99 they were switch box type ignition.. 2000 up they were cdm, 'lectronic type ignition.. is tha thing a switch box type or cdm (all 'lectronic) assuming you know what tha difference is.. one way to tell is by looking at tha "coils".. cdms are three on each side but mounted separately.. coils will be three to a side but by a single (3 coils) plastic mounting "holder"..


look on tha starter solenoid and see if there are "two" yellow/reds on small pole...


tha tps adjustment may help....


stump, completely different motor.. his is mechanical pump "first" that feeds tha efi stuff..

TLW, it appears the coils (3 each side) are all contained in a single housing.

TWL, yes on the yellow reds

its still a "switch box" motor.. may need some pictures of tha powerhead.. 2000 up block has different mounting bosses' for electronics.. ie: cdms, plate on starboard side.. also has 0-ring heads ta make up difference of tha block being 40 thousands "taller" at cylinders.. it could be an oem "replacement block" built in 20??.. there is a "build date" stamped on tha block.. i'lll try to explain where it is..

port side, at tha base of number 2 cylinder on tha "block" (rear/back) half, kinda right behind tha bend in tha timing arm there will be 1/8" numbers stamped.. mo/day/year.. might be hard ta see but they are there..

one of tha yellow/reds goes to tha ecu.. that is an enrichner circuit.. it supposed ta fire a coupla injectors every time ya hit "start".. one of tha reasons efi's are supposed ta start so easy.. if that circuit goes out it will act exactly like what you're describin'.. only seen one like it and tha guy replaced ecu before we got a chance ta see if it was a way to get around it....

"qualify" "replaced boat".. traded it in!.. sorry.


send an email and I will send ya an oem manual in pdf if you would like....

you might wanna check tha mechanical pump for out put and pressure ....