Engine turns over, but won't start.

yppirsr

I have a 2008 Rinker 350 EC, with twin 350 mag mpi(s).   Engines have been starting and running fine to date.   Started port engine, then shut it off to fuel.   15 minutes later, engine would turn over fine, but not start.   I can hear the fuel pump cycle when I turn the key on.   It is getting fuel.

What can cause it to not fire.  Fuses, breakers, distributor cap or rotor??   Anybody else have this problem.

Running fine 1 minute, then it will crank fine, but not fire??

aero3113

Check to see if your throttle lever is in neutral.

Aqua_Aura

It doesn't start at all? If it starts eventually maybe some sort of vapor lock which happens to me on occasion. 

aero3113

Also, it could be your IAC valve. Try to give it a little throttle and see if it will start.

Aqua_Aura

There it is. I thought maybe you would mention that in the first comment 😉. That dam IAC valve sure does seem to cause a lot of problems, gets mentioned in every thread. 

PickleRick

If it did it right aftert a full up id check for water in the filter.

aero3113

PickleRick said:

If it did it right aftert a full up id check for water in the filter.

I would think it would’ve at least started for a couple of minutes after fill up.

PickleRick

He said 15 min later did he not?  Its still early lol

aero3113

He said 15 minutes later, I’m assuming after fueling it wouldn’t start.

69fastback

Does the other one start? If not, kill switch?

PickleRick

Im glad my diesel doesn't have an iac

212rowboat

if you suspect the IAC, just bump the throttle open a little... that's all the IAC is doing anyway.  

check fire.  fire is most easily check with a can of starter fluid- sprayed carefully and directly into the throttle body, only a momentary pause, and then turning the key to start... if it coughs or tries to run? you've got fire and your issue is fuel or air. 

if it doesn't cough- it's fire: start at coil- use meter to see if it is lighting up... then follow to dizzy- see if the 'other' end is lighting up... check key switch- pull it out and see if the run wire is dislodged.  check kill switch... they give up the ghost too, so even if it is in right position jiggle it a bit... chase ignition wire to engine- see if there is power off the 90a fuse mounted on the starter... you 'can' bypass this fuse by removing the 90a fuse and bolting directly to the starter post, but you're not going to want to leave it that way for long...  

this has got to be simple.  don't make it any more complicated than you have to.. 

an IAC will keep you from idling.. it will necessitate more throttle (from you/lever) off idle.. it will sometimes make you have to open the throttle a little bit while trying to start... it won't prevent the engine from starting or at least coughing unless something else is going on.  

davidbrooks

My dad taught me how to check the spark by having me hold the bare sparkplug wire while he tried to start the motor. If i jumped we had spark.

aero3113

davidbrooks said:

My dad taught me how to check the spark by having me hold the bare sparkplug wire while he tried to start the motor. If i jumped we had spark.

LoL! Good way to learn!

rasbury

Go with the obvious like 212 says.. beyond that, to much electronics ..crank sensor, cam sensor...computer...

yppirsr

Would the boat not being completely in neutral allow the engine to turn over but not start?

aero3113

Yes, that’s what I mentioned earlier.

davidbrooks

@yppirsr for me if it isnt fully in neutral it wont turn over. 

rasbury

I'm with David. Aero,...come to fla. 
and hold my prop and I'll give it a little bump. Just kidding but sometimes I think it's all the protect us from ourselves systems are the main issues.
Dam, I'm starting to sound like a Republican....lol

yppirsr

Problem solved. New distributor cap and rotor did the trick. Thanks for all the input.

aero3113

Great, thank you for the update.

212rowboat

davidbrooks said:

My dad taught me how to check the spark by having me hold the bare sparkplug wire while he tried to start the motor. If i jumped we had spark.

i was a gullible kid... i am a cynical adult. 
my buddies dad told me to hold a plug wire to my lip- i did.. he hit the starter.  he didn't think i'd do it, or so he says.. i was probably 5 years old.. 
i once peed on an electric fence to 'see the sparks'.. same guy suggested it, but i did it when nobody was around.  it was a pulsating charge, glory be to allah, so at first all was well- then the world became and exciting place until the charge passed.. then i got mad... and i mean mad. i was likely seven or so years old.. 

i got him back....some years later... i'll share that tale another day. it had to do with his horn connected to his brake lights switch while leaving a college football game.... where he'd parked among the rivals... he. was. livid.  so mad, in fact, we're not friends anymore.