Hard Start When Warm

I'm concerned about the leaky injector theory because of this test I performed on the last day of my last trip 2 weeks ago. Woke up on the last morning and fired it up in the slip (key only, no throttle advance)... Let it idle for a few minutes while I untied and stowed dock lines... idled to pump out dock about 5 minutes away... shut it off at the pump out dock and immediately tried to restart with no throttle advance and it just cranked with no start.Would the injectors leak enough that fast to flood it ?

pumped out and had to use full throttle to get it started. Put it on trailer and took it to storage.

My mechanic said he ran it on the muffs for 20 minutes, shut it off and it restarted with key only multiple times. I'm baffled.
 
I was just looking for a cause for excess fuel to get into the cylinders.

If the injectors were leaking, the fuel pressure would drop, sending a signal to the pump to bring pressure back up as in first starting cycling.

OR in other words...
Turn ignition on (not starting) and listen for pump to cycle intermittently due to pressure drop from leaky injectors.
 
I plan to do so when I go up to the boat next weekend. Thanks for all your advice.
 
quote:
Originally posted by j-d

There are all too many "MerCruiser Mechanics" whose minds are still in the Points/Condenser/Carburetor/Mechanical Fuel Pump stage.

Click to expand...


LOL, jd is on something :D.

I don't think you have the injector leaks problem, if your injector/s is/are leaking, you would have "misfires" feeling on cold start and somewhat "jerk/buck" when on accel. I had same problem with my MPI years ago and that's why I don't think it's an injector problem.

Mine happens more so when my gas tank is below 1/4 and after ran it hard(wake boarding) then shut it off for more than 1/2 hour.

Next time when it happens, try something new. Do not "full open" throttle when it failed to start at first, try to turn the ignition off, wait for few minutes, turn it back on but do not crank, and turn it off again and then after few minutes later, try to start it normally (w/o wide open throttle), if it's stills not started, open engine hatch and do the key cycle again for couple of time then try to start again, if it's started, it's not injector leaking problem.
 
Update:

Had the mechanic do a pressure test on the fuel rail and there was not a drop in pressure over a 6 hour period.

Question:
Someone mentioned the engine temp sensor. Is that the same sensor that drives the temp gauge on the dash?
 
Usually two seperate sensors, one for the gauge and one for the ECU
 
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