240hp merc hot start/poss flooding problem

[DanDiaz803]

new to this forum...so much helpful info..upon reading another "hot start" experience by scarfie, have tried a few things, but here goes my version.

have the 2002 x20 240hp Merc EFI engine..have owned about 8 months...started having problems starting when engine is hot about a month ago and it has been a very frustrating experience...had "re adjusted the accelator setting to rev higher in neutral and to gain more top speed, but thought it was the reason for starting problems so had a mechanic reset...after a few start problems, replaced battery, then cylinoid (not proper name im sure), then had the starter worked on, thinking it was always an electrical problem...have replaced the spark plugs (don't use other than factory!!!) and have ordered a new temp sensor to be in next week.(as advised by another thread)....today, same ole problem...starts fine cold...a lil runnin around, even @ no wake speeds, won't restart until it cools off....a seasoned boater who works on his own engine told me it is flooding and that he can smell it flooding out....direction please...not sure i understand vapor lock issues either...

 

[rookie101]

When it will not start does it turn over and not fire, or not turn over? Need a little more information on the actual symptoms.

If it's turning over and not firing, first things first, check for spark. If that seems OK, try spraying a little carb cleaner down the intake and see if it fires. If it is flooding, you could have a bad temperature sensor, or something like an injector leaking down.

Check for spark and the fuel situation, and let us know from there.

Aaron:cheers:

 

[DanDiaz803]

thank you in advance for the reply.....ok, ran it around today....got the motor runnin' hot...came back to dock it before turning it off...and voila...didn't start, so i checked each of the spark plugs and they are all firing just fine (lil jolt felt on the 1st check, then used pliers to verify spark on a ground).......funny thing is...it started after checking the plugs...did notice the plugs were wet/dirty even though 4 of the 6 are brand new...left the boat sittin for about an hour..came back and loaded it on the trailer and turned her off....tried to restart w/water hose to flush...no start again....took off each plug and cleaned/wiped dry...no start again.

as far as spraying carb cleaner...is it safe to use on the EFI system? am i to understand that even though it is EFI the carb cleaner will work?...have been reading the service manual to familiar myself a bit....have ordered the temp sensor like a previous post suggested....but if the problem is flooding, will replacing that sensor do anything? wouldn't a faulty sensor PREVENT fuel from gettin' in rather than flooding, or do i have it all wrong?

 

[rookie101]

A small bit of carb cleaner down the intake just to see if it will fire is fine. Just remember you're not trying to run the engine on carb cleaner, jut seeing if it will fire.

Your thinking on the temperature sensor is a bit backwards. You have to think of it as your choke on warm up with a fuel injected engine. When a motor is cold it requires much more fuel to run smoothly then when warm. Because of this when your engine warms up and you shut it off, if the temperature sensor is telling the ECM that your still at the same temperature as a cold start it is going to tend to want to flood.

Give the new temperature sensor you ordered a try and let us know if it solved the problem.

Aaron:cheers:

 

[DanDiaz803]

thank you for the explanation rookie101...will anxiously await the air temp sensor to come in and try it out...will advise...been reading that you have replied to many posts similiar to this....think you should come up with a manual..."seadoos for rookies"..lol...thanx again...also, was there ever any other manual uploaded for 2002 Merc engines?? i realize from your info they have changed them a bit...

 

[rookie101]

Sorry still just the manual for the first generation 210/240. You can check with the admin Joez to see if he has a newer one ready to go yet.

Aaron

 

[boeing747arowair]

if intake is dirty spray the helll out of it with throttle body cleaner and go fromt here

 

[DanDiaz803]

okay, was finally able to replace the air temp sensor and go the time to go out and test drive it...unfortunately, still the same problem...starts great but after use/engine hot, it does not start and still feels like a flooding problem..haven't tried the carb cleaner @ time of not starting, but will do next time..any further advice?

 

[rookie101]

okay, was finally able to replace the air temp sensor and go the time to go out and test drive it...unfortunately, still the same problem...starts great but after use/engine hot, it does not start and still feels like a flooding problem..haven't tried the carb cleaner @ time of not starting, but will do next time..any further advice?

I was thinking more of a cylinder head temperature sensor rather than the air temp sensor. Download the M2 manual, and it will give you the resistance specs for the sensor at different temperatures. Bring a multimeter along with you on your next outing.

Aaron:cheers:

 

[DanDiaz803]

okay, was able to test the cylinder head according to the specs on the M2 manual...it responded well and very close to the paremeters when placed in cold water @ approx 70*, so it seems that it is no the culprit to my problem...next step?

 

[rookie101]

okay, was able to test the cylinder head according to the specs on the M2 manual...it responded well and very close to the paremeters when placed in cold water @ approx 70*, so it seems that it is no the culprit to my problem...next step?

You're not done with the testing. The problem you're having is with a hot start, not cold. You need to get the engine hot and see what the sensor reads. If it is still telling the ECM that the engine is cold, or it's resistance value goes to open when it gets hot you will flood on start.

Aaron:cheers:

 

[SJackson]

We are having the same problem with our Seadoo Challenger 1800 - do you know wear we can order the sensor you are talking about? We have looked and cannot find anyplace to get one.

 

[DanDiaz803]

makes sense rookie....so i came out to do the engine head temp sensor test...didn't get a base setting cold, so i decided to take sensor off and test it w hot water same as i did w cold...and it does seem to be working properly..the resistance changes inversely with the temperature change...next i will reinstall and make sure it is making good contact, and get a base reading and test again when hot (if it starts..been trying for 2 days now and is giving trouble even starting cold..first time it does that in all the fiasco...now where do we go from here?..what is my next step after testing the cylinder temp sensor?

jackson, if you can't find anything, my local dealer is a merc rep..should be able to ship out items..info is:
Bayside Marine
956.943.1551 in texas

 

[rookie101]

Recheck the sensor on the engine if you can, starting with a cold reading. Also remember that you have two cylinder head temperature sensors, a port and a starboard.

Just a couple of other quick checks are, make sure the arm going to the TPS is adjusted properly or it will run really rich, and put a volt meter on the battery when you crank it. IF the voltage drops below about eight or nine volts on crank it wont start. A few more things are to check the vent hose for the vapor separator to see if fuel is running out of it which would indicate the needle or float are stuck, and pull the vacuum hose off the fuel pressure regulator and make sure there is no fuel present.

Aaron:cheers:

 

[jay40716]

I am having the same exact problem. I have already ordered a temp sensor and I am replacing it today. After this temp sensor im running out of ideas. Please keep me up to date because im basically following along and doing the same steps you are. Thanks. J

 

[johnhibbs]

Me Too! 240EFI M2 hard hot start

I have the same problem. When my engine warms up I have a hard time starting it sometimes but not always. I have learned to turn the steering wheel hard CW or CCW to give the engine a little higher rev than the 1000 rpm at idle. Turning the wheel hard against the stops revs the engine to 2000rpm.

I asked my local Mecury parts dealer and if he thought it could be the starter. Even though it's engaging and turning it might not be turning fast enough. I may spend the money just to find out. I see that ebay sells them for around $130.

 

[johnhibbs]

Starter getting hot after engine shut off?

My theory is that when the engine is shut off the engine gets hotter because it isn't cooled with flowing water any more. That may heat up the starter and it may not work as good. I have been thinking of taking a water spray bottle with me next time to cool off the starter to see if I'm right.