f115 2005 hesitate, bog, sometimes hard to crank

2005 f115 - I have twin engines, beginning of the year I went out and after sitting the winter had a water/fuel issue very severe on starboard engine, replaced 10 micron first filter ...emptied the first filter in motor...treated gas and all is good.

on the port engine, the one that did not give me a problem the first day (no water in the filter), I replaced the first filter with a racor when I did the starboard side. I noticed while I was underway a skipping, it was not a bog down, just a little skip, watching the tach you could see it bounce around...this would happen after I had been underway for a minute or so, then after a couple of minutes it would go away and run great.

The problem got a little worse next time or two out and cold be described as a skip and sometimes a bog (felt like I had run aground for a second)....I cleaned the injectors and replaced the filter prior to the pump in the motor.... no change in symptom.....

took off on a fishing trip...motor ran rough for a while then great...ran about 35 miles....sat on idle while drift fishing...when I started home...same thing ran rough for a while then settled down....this was after never cutting off the engine while drift fishing.

I went ahead and swapped injectors from port to starboard.....I put it in yesterday for a test run, problem stayed in port, eliminating injectors.....when I first start out the engines seems fine even at 4k rpms...giving me the fleeting feeling that I have fixed it....within the first minute of running it starts the skip/bog thing again, mostly skip.....after 2 miles out I dropped the trottle to idle and the port side died and would not re-crank....limped back on one engine, put it on trailer and while still in the water got it to crank with the trottle advanced in neutral and would drop back to idle and run...while in the water put it in gear and it ran with the skips again, when pulling back on throttle it quit...

One other thing, when I turn on the starboard key the system beep beep beep and does not stop...on the port side it will beep twice and stop...not sure if that is a clue


I am at a loss on this and I read about the vst filter, I am unsure how to locate that...I am desperate for some ideas......help

got a fuel pressure gauge and while the motor was bucking and sputtering the high pressure rail was measuring 40 - 42 PSI so I think I have eliminated filters......

so, last night, I swapped between the engines....both coils...and put new spark plugs in......still no real luck....desperate here...help.

......

thanks Chris, I was pretty sure I was all alone on this one, your response gave me hope.....

For the rest of you readers, I swapped parts between the twin engines, one after another. When I got to the ECU, the problem was not duplicatable on either engine. I did a significant sea test today and both motors ran great. I am guessing there must have been a bad connection of some sort on the ECU.

Sorry Brother, I missed the line in your first post about swapping the injectors.

Now that you have located the possible problem, I would clean both ECU's and both Connectors. If there was a little corrosion on the one you had a problem with you just transferred part of the problem to the other engine and in time they will both break down.

Docksidemarineservices said:

Sorry Brother, I missed the line in your first post about swapping the injectors.

Now that you have located the possible problem, I would clean both ECU's and both Connectors. If there was a little corrosion on the one you had a problem with you just transferred part of the problem to the other engine and in time they will both break down.

Click to expand...

I will keep everyone posted, so far so good.