Mercury Motor wont start when hot out.

**Bass man** · 08-07-2018, 06:11 PM

I have a 2001 Mercury 200Efi. Ser#0T391419.
I’m apologizing in advance for the lengthy post. I had my motor rebuilt 3 years ago,ever since then I’ve had nothing but problems. First of all the hole shot went away,so I took it to the marina the following year after they rebuilt it. They had it for a week found nothing wrong said I need a different prop, they changed me $600. So I tried some different stuff with the prop ended up drilling extra holes in it. Helped a little then about that same time I was experiencing the motor not wanting to start, figured out when it got hot outside it wouldn’t start. So I figured out when it happened I had spark and fuel pressure, fuel wasn’t hot. Sprayed with carb cleaner then it would run for a couple seconds. Then I decided one night when it wouldn’t start I would strap an ice block to the Ecu tried it an hour later started and ran fine. So figured Ecu, sent it to Simmons to have it rebuilt got it back same thing no different put block of ice on it again hour later it started. There saying it’s not there problem. Another $800. So now Im stuck again. List of things I’ve done in the past year. New fuel pump,thermostat impeller and 3 sets of plugs, new Cdm box. Tried a different trigger checked stator and cdm. So I need some help tired of throwing money at it. Thanks Rich

**Merc 2.5** · 08-07-2018, 06:38 PM

If it has spark when hot and wont start , I'd check values of stator. Could b just weak spark doing it,

**rkmirage** · 08-07-2018, 07:53 PM

Did you check the tps?

**Bass man** · 08-07-2018, 08:53 PM

Yes they did adjust the tps when they had in the shop for a week. Thanks

**Bass man** · 08-14-2018, 01:41 PM

Still looking for help! Took the boat out last night took a 5 minute ride,trolled for an hour and half. I go to start it to move started and killed right away like it does then it wouldn’t start again. It was overcast and only 83 degrees out. Took the cowl off felt the block felt pretty hot to the touch. Wondering why it would be so hot on a 5 minute run. Thanks again

**eli** · 08-15-2018, 08:59 AM

143 degrees is hot to touch what happens after long run them let it idle for minute

**Bass man** · 08-15-2018, 09:16 AM

Thanks Eli, I will have to try that this weekend. Normally I’m Fishing tournament’s so that is one of the last things I think of. I was wondering would it still be that hot 1&1/2 hours later? Thanks again.

**flabum1017** · 08-15-2018, 06:39 PM

Just so I understand, you are saying it won't start when it's hot outside and the engine has not been run yet? Sounds like a faulty temp sender. If the temp sender is telling the computer the engine is 150 degrees and the engine is only 80, it will be hard starting or not start at all. Had a couple of them do that to me. Best way is to scan it and see what the computer is saying the engine temp is. It will not throw a code if it's doing this because the computer is looking for a range that the sender should be in, let's say -30 degrees to +250 degrees..... if the sender is reporting within those numbers, it will not throw a code but report the wrong temp to the computer...... clear as mud?

**Bass man** · 08-15-2018, 06:52 PM

Sorry flabum1017, It runs great till the temperature outside gets hot. Then after Fishing for awhile I go and start it and it just turns over but wont fire. So could it still be a faulty temp sensor reading that it’s to hot? If so where is it located? I’ll have it out Saturday if it don’t start I’ll take a infred thermometer and check temp of block. Thanks

**flabum1017** · 08-15-2018, 07:09 PM

Originally Posted by Bass man

Sorry flabum1017, It runs great till the temperature outside gets hot. Then after Fishing for awhile I go and start it and it just turns over but wont fire. So could it still be a faulty temp sensor reading that it’s to hot? If so where is it located? I’ll have it out Saturday if it don’t start I’ll take a infred thermometer and check temp of block. Thanks

Oh, OK, disregard, I've never seen a faulty temp sensor prevent a warm engine from starting. Almost sounds like vapor lock you are experiencing since you say it will start for a couple seconds when you spray carb cleaner in it. So it's sounds like you are not losing spark, but you can verify that with a spark checker.

**eli** · 08-15-2018, 07:28 PM

Don't use carb cleaner use fogging oil instead for tests 1 hr later it shouldn't be that hot find a temp gun see how hot its getting

**Bass man** · 08-15-2018, 08:28 PM

Thanks again flabum. Eli thanks too. I took it to the Marina on a day it was hot outside ran it for 20 minutes then let it sit for an hour. Tried starting it, it killed right away. Thats when we checked it for spark,fuel pressure,hot fuel and used what I thought was parts cleaner but was probably fogging oil.
Thanks again for trying.

**flabum1017** · 08-15-2018, 08:52 PM

Actually, better to use a spray bottle with gas/oil mix...... J/S

**eli** · 08-15-2018, 09:42 PM

Fogging oil is great the motor will run on it and puts oil in the motor. We winterize motors and with a little spray in the spring They fire right up no dry starts