Optimax 225 hard start

[makobruh]

Hey guys, just got a new to me 1999 Merc optimax 225. At first I couldn't get to start at all and then I read optimax doesn't like to fire on low voltage and it was dipping to 10v while cranking is that true? Seems like if the engine can spin it would fire... so I put the charger on overnight and boat started right up on a full charge but it would not rev, is that cause I tried to rev it cold or maybe tps? Restarted and then it reved fine, just up to 900rpm as I heard not to rev these motors. I idled it for 15 min and after it still started but turns a few revolutions before firing. A few times it fired enough to disengage the starter but didnt fully fire. Is that normal for that motor? Im coming off a 2003 carbed 150 that is a pain cold but starts warm with just a starter bump.

Compression is good, going to check fuel and air pressure as soon as I get a Guage. Supposedly the fuel system and filters were replaced before the boat was put up last year in October but I may do it all again.

 

[QBhoy]

Battery, charging output and or fuel quality, would be the suspects for me.

 

[dingbat]

The motor is very fussy about battery condition. Mercury recommends a minimum of 800 CCA (1,000 MCA).

 

[makobruh]

What do you guys think about using a big 1000+CCA automotive battery instead of a marine battery?

So the motor should start easily right? This is not typical optimax behavior?

 

[dingbat]

What do you guys think about using a big 1000+CCA automotive battery instead of a marine battery?

Not a fan of using automotive batteries but it’s your coin

So the motor should start easily right? This is not typical optimax behavior?

When everything is right….
Filters clean?
Air and fuel pressure in specification?
Any idea last time the injectors where cleaned?

 

[makobruh]

No idea on injectors so I may need to look into that. I am going to run the engine on a portable tank with some quickleen and then on regular gas to see if anything changes. Was told filters were all replaced at end of last season and look new. There is an inline filter that hasn't been replaced that I'm replacing this weekend.

Going to check pressures as soon as my gages come in.

Is there any way to get a code reader for these engines? Mine doesn't even beep on key on.

 

[QBhoy]

Might also suggest you prove the ignition key switch is ok. Just from my recent experience with my merc there. Check the neutral safety switch too.

 

[makobruh]

Checked the fuel and air.
Air was bouncing around 80 and fuel bouncing around 90.

Ordered new fuel filters and a starter cause it was making a noise and I like to have a spare anyway. Going to fill the filter with seafoam on install and add quickleen to the fuel. Going to take the boat out and run it and then change the plugs and see where we are at.

Anyone know about pulling codes? Would be amazing if I could hook the engine to the simrad somehow.

 

[dingbat]

Not knowing their condition, the injectors should to be sent out to be cleaned and calibrated.