03 M2 opti 200 hp- still having a hard start issue.

[nokwit]

This is a continued issue..

Starts up when cold. Let it run for a bit and shut down and now it starts stalls starts stalls starts stalls a few more times...Give it some throttle and if I get lucky it’ll run. A minor idle rpm surge. Runs great if you can get it going.

- replaced filters
- new plugs. Old ones were platinum. Now iridium.
. Cleaned plug wire connections.
- DFI injectors were sent out and cleaned and tested. Thought this would fix. They cleaned first and then tested so I didn’t know if any were leaking before cleaning.
- Air injector tips and cleaned with seafoam intake cleaner and toothbrush.
- vapor seperator inspected for varnish build up.
- two new 1000 cranking amps marine batteries.
- Always get the single beep before cranking at key ON.
- lift pump runs.

I’m out of ideas. Last time it almost left me stranded after shutting it off to fish. I couldn’t get it to start even with full throttle. I bled the fuel rail off cranked. Bled it off again cranked and repeated and finally got it going with full throttle.

TPS sdjustment?

 

[Dr Honda]

Couple things off the top of my head....

1) Have you checked the air and fuel pressure after it's warmed up? That's not normally an issue (from cold to hot) but it can happen.

2) Are you running the bilge fan? I know you are probably opening your deck lid... but the fumes need sucked out of the bottom. (Fuel fumes are heavy)

3) Have you looked for any exhaust leaks? Here again, not normally a problem, but we've seen it twice ont he forum this year.


Yes... it can be the TPS, but it will normally trigger an alarm if it's out of rage. But check. you are looking for 0.4v to 1.3v in the idle position.

 

[nokwit]

I attached a vid from ipad but it’s be too long or wrong format. It captures a successful cold start, idling. Bled some fuel to remove any air in gauge as needle is bouncing. Checked for leaks at schrader connection. Then gave it some throttle to see how pressure reacted. Got temp warning beep. Shut it off. Cranked and almost went. Followed by some more unsuccessful cranking with some throttle on the last attempt. You can hear the noise change as butterfly opens increasing air flow.

 

[nokwit]

Here’s the youtube link to vid.

 

[Dr Honda]

Looks like your fuel pressure is good. Check your air also.

Was the meter just on the battery?

 

[nokwit]

Yes the meter was on the battery. I will connect Merc G3 software again on Wednesday and log some data which captures ECM battery volts. I don't get many parameters with this software.

I will measure the air pressure under the same operating conditions as I did the fuel.

 

[nokwit]

Here’s the air press measurement. Engine actually stalled out after revving it up after first start up.

 

[Dr Honda]

Hummm....?

So... fuel, and air are good. I'm having a hard time reading some of the descriptions on the computer... but they seem to be OK too.

The stall out almost seemed electrical. Try this... lift the Black/yellow wire where it comes into the engine harness. I'm almost thinking you have a bad key switch or lanyard switch.

Where did you get the Merc software? You can PM me if you don't want to talk about it on the board.

 

[nokwit]

Is this the wire you're referring too?

 

[nokwit]

Snap shot of data while cranking upon restart attempt. I don't see anything out of the ordinary although there's just some basic parameters to view. Wish there was some advanced parameters like spark volts, timing deg, etc...

 

[nokwit]

So I disconnected both starboard and port temp sensors and it starts instantly and idles strong. Tried unplugging one at a time before in early t/s stages and it had no real affect. Assumed temps were correct as all temps were close. Just picked up my infrared temp gun to see if temps match ECM values.

 

[nokwit]

Verified port, starb, comp, and intake temps are all within a degree of ECM value. Default value for any temp sensor when unplugged is 32F.
Retested and same results... With port and starb temp sensors both disconnected it will start up everytime. It’s starving for fuel when cranking. Fuel injectors had new screens installed also as they were dirty.

Is there a fuel map relearn procedure on these engines? Since it’s a two stroke, can I run it rich like this temporarily to get family out on the water? I guessthat would depend on whether cyls load up and start causing some fouling or not.

 

[Dr Honda]

Yes... that was the wire I was thinking about... but it sounds like you found something.

I never like to recommend running in a condition that is unknown. With the sensors disconnected... it is supposed to go rich. BUT, since it's already lean.... then we really don't know how it's running. I know on the 240 engine... those sensors trim the fuel. (up to 40% more) But at full power... it's not looking at those sensors. SO... if your injectors are running lean for some reason... then at full power, it may be going lean. If this was a 4-stroke... I'd say to go for a ride... but on a 2-stroke... it could be a melted engine. So... that one is up to you.