1999 Merc 225 efi dying after dropping down off plane into idle

[Highrisk]

Ok guys it's kinda of hard to explain but here goes.Last weekend I took my son fishing and when we would drop the boat down and start to idle into where we were going to fish the motor would just go dead , when You would try to restart it would not crank but after fishing for awhile it would start right up, so after a day of that I came home checked the bulb , gas pickups , plugs , fuel water seperator and found nothing. The boat with ear muffs on would idle for only a couple of minutes and then go dead. Soo I waited a day and ran it again with ears muffs and it would run all day on either tank without missing a beat..So last night I figured I would try my luck again on the water so put a bottle of sea foam and the motor ran great right from the start all the way to my first spot which was around 3 miles away and as soon as it dropped down dead again , so fished for around 2 hours and she fired right back up till the next spot and so on and so on...got back to the ramp died again but after about 2 minutes of turning it over it started up again so I tied her up went got the truck and it idled the whole time loaded it up and came home..its almost like the idle needs to but turned up(if thats possible or it's loading up on gas...I'm not sure...any ideas?

[kllr bee]

How long has it been since you put a waterpump in this motor. Reason I ask is that idling shutdown after a long run could be caused by the motor getting hot due to overheat from low waterpressure at idle speed. do you ever get a solid buzzer from warning horn.
Richard

[Highrisk]

This is a new boat to me , I have only had it about a month so not sure about the water pump,,,but there arent any buzzer or alarms.

[JAZII]

Have a link and sync done by a qualified Merc tech.
Your TPS setting might be off some.
A water pump repair kit would also be a good thing to do, since you have no history of when it was last changed.

JAZII

[EuropeanAM]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by JAZII &raquo;</td></tr><tr><td class="quote">Have a link and sync done by a qualified Merc tech.
Your TPS setting might be off some.
A water pump repair kit would also be a good thing to do, since you have no history of when it was last changed.

JAZII</td></tr></table>

+1

You may also want to take a closer look at your FUEL LINES/ PRIMER BULB, as well as verify that your fuel tank vents are not plugged.

See the following post in regards to fuel lines:

http://www.bbcboards.net/zerot...first

[Highrisk]

update..I finially had a minute to get started on finding the problem..I pulled the hoses from the tanks and eyeballed the pickup didn't see anything there but I'm gonna replace the hoses tomorrow but as I disconnected the bulb hose and fished it out from the hose vent when I got it out it had been cut and spliced back with a hollow tube in the middle and two zip ties...needless to say I will be replacing it also...man I hope this is the problem...

[Highrisk]

I replaced the both fuel lines,change over valve and bulb and so far so good. I did have a small episode saturday though. after fishing for a while I was idling out into the main river channel looking for another place to fish and my alarm went off and the boat went dead. I tried to restart and it would not even turn over so I waited a few minutes and tried again with no more problems until I got ready to load the boat it died again and would not even beep with the key. I got home and check my battery and the terminal was corroded so I clean them really good and went fishing last night and everything worked like a charm...could this have been my problem the whole time?..Btw thanks Don for taking the time to call me back last week.

[EuropeanAM]

Battery connectons could definitely have an adverse affect.

If your loss of ignition switch function occurs again, you may want to look into the cannon plug (ignition switch harness connection at engine) to ensure that it's clean, spread the male pins SLIGHTLY with a small pocketknife, and reassemble. Make sure the connection is tie-wrapped to the engine so that it cannot "vibrate".

[kllr bee]

Also on the battery connections I always use grease on my terminals to keep them from corroding.
Richard

[Highrisk]

Ok I'm about ready to just stick some dynomite in it and write it off ! Fished yesterday and it ran fine for about the first hour and then when I got ready to move it cranked fine, idlled fine but when you mashed the gas it would just bog down and would not come up onto plane. I got my partner to stand on the front of the boat to get it to plane off and it woyld run fine turning around 5000 rpm's but as soon as you would drop it down it would do the same thing again.finally after idling back it just went dead and would not start..got home cranked right up..I went ahead and changed the plugs and went back today..same thing ran fine on the first run after that same thing..with the gas all the way to the floor only around 2600-2800 rpm's but you could put in nuetral and rev it up as high as you wanted...sooo idled back once again and I saved the best for last ...as I was idling back I wet to cut the bilge pump on and as soon as I did it died..didnt fire anymore after that ...strange I know...needless to say I fished all the back ! and ideas?? I'm to the boiling point...thanks

[hsteven916]

I having the same problem for almost 2 year now and still trying to find da problem!!!!!

[EuropeanAM]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by EuropeanAM &raquo;</td></tr><tr><td class="quote">
If your loss of ignition switch function occurs again, you may want to look into the cannon plug (ignition switch harness connection at engine) to ensure that it's clean, spread the male pins SLIGHTLY with a small pocketknife, and reassemble. Make sure the connection is tie-wrapped to the engine so that it cannot "vibrate".

</td></tr></table>

If you can get your hands on a "transom test harness" (this is a separate ignition switch and harness that plugs directly into the engine).... it will help to clarify if there is a problem in your boat wiring.

You can either plug it directly into the engine and go run it (to see if the problem is gone).... OR, you could run on your current harness, and, when it acts up again, swap to the "test" harness to see if the problem "ceases".

I suspect you DO have a problem in your keyswith, killswitch, or harness.

[Highrisk]

I got in touch with best Merc Mechanic in these parts so she is going under the wrench tomorrow for some open cowl surgury I will post what is found..