K im fairly new to boating just bought my first one this year from a close family friend. Its a 2003 VIP with a 4.3L Mercruiser EFI. Im pretty mechanical, worked on many things throughout my life but total rookie marine mechanic now. Anyway I purchased the boat in winter, as far i knew it was winterized properly so when the warm weather came about i put another 60 bucks of regular into it and filled the tank. I've taken the boat out a couple times with no problems, always started good and always ran good. On May long weekend I had the boat wide open for a little while and probably had it trimmed up a bit too much cause i caught a weird wave and made the boat go a little snakey for a quick sec. After that i powered down to idle quickly and then shut off the engine right away. When i idled it down for that brief moment it seemed to still be running good from what i recall.....so i turned the ignition off, we just sat around for a brief couple minutes and talked. I went to go start the boat and nothing........it turned over and over and over and over. I was in complete disbelief why it was not starting especially an EFI. After a bit of cranking i figured it might be a good idea to give it some throttle and sure enough it fired and it seemed alright at a high RPM throttle but the second i'd drop it back to idle it would want to die and sputter. So after a couple minutes of trying to get it to go i finally got it to go from idle in to gear so we could get back to the boat launch on our way there it ran a lil weird on my low rpm's for a few seconds until i gave it more throttle and then it was back to life and back to normal. I just figured i flooded it and its ok now. But when we got back to the boat launch it was the same thing, took down to idle expecting it to be ok but no......it just wanted to stall out.
The next day i put the muffs on the boat expecting the same thing, that its not going to want to run.....but no it fired right away and ran. It idled at around 700 rpm but it was a rough idle, it loped and sounded as if the engine was cammed. It never at anytime seem to want to stall tho. So again i thought whatever it was its good again.* So the boat has sat for a while and we just decided to take it out again this weekend thinking that the problem was gone because it was idling fine in the yard. So we put the boat in the water and started it. It didn't start "as good" as it usually would of but it wasn't ran for a few weeks so i didn't think much of it.* The main thing was it started, (engine cold) and it was idling in the water (under load) now....so i was happy. So we went touring around and found a spot to go fishing after a little bit of a drive and again everything seemed all well and good at higher rpm driving around and sure enough as we found our fishing spot and i went to idle down it was sputtering and not itself. So i killed the ignition and we fished for awhile and again when i went to go start it.........nothing! I once again had to give it throttle in order to start, once i got it going i had to throttle up and then quickly try to go down to idle and then hope for the best i can get my prop to engage. After a few failed attempts i was able to get it to engage and we drove in (once again running fine at high rpm).
After coming in i checked if my injectors were firing normal and they seemed to be spraying fine. So i kinda ruled out the lack of fuel there. The next thing i went to was my distributer cap....i seen my contacts were corroded a bit so i shined them up a bit and figured that this had to be the problem. Corroded points not putting enough power to the plugs. So we dipped it back into the lake again and nope..........still nothing. It would only fire on throttle and didn't want to idle.* So now today after more reading i found a few forums with a couple guys who have similar problems as i do. I checked my exhaust shutters and they seem fine, i also have had the battery charger on my battery all day (not to mention) a new battery from last year......so im not sure if that could be it. I fired up the boat not long ago hoping perhaps it was the weak battery and it started right up and for a brief couple seconds it idled strong at 1000rpm on muffs, but then quickly went down to 700rpm and would lope and sound like it would want to die. So im completely stumped!? Whatever happened it all started from that weird wave i caught, it cant be fuel because it seems like my injectors are working 100%.......im thinking it has to do with spark or lack of!?! But would definitely like to hear what anyone else thinks! I would like to get this problem fixed and also save myself the few bucks not taking it into the shop.
The next day i put the muffs on the boat expecting the same thing, that its not going to want to run.....but no it fired right away and ran. It idled at around 700 rpm but it was a rough idle, it loped and sounded as if the engine was cammed. It never at anytime seem to want to stall tho. So again i thought whatever it was its good again.* So the boat has sat for a while and we just decided to take it out again this weekend thinking that the problem was gone because it was idling fine in the yard. So we put the boat in the water and started it. It didn't start "as good" as it usually would of but it wasn't ran for a few weeks so i didn't think much of it.* The main thing was it started, (engine cold) and it was idling in the water (under load) now....so i was happy. So we went touring around and found a spot to go fishing after a little bit of a drive and again everything seemed all well and good at higher rpm driving around and sure enough as we found our fishing spot and i went to idle down it was sputtering and not itself. So i killed the ignition and we fished for awhile and again when i went to go start it.........nothing! I once again had to give it throttle in order to start, once i got it going i had to throttle up and then quickly try to go down to idle and then hope for the best i can get my prop to engage. After a few failed attempts i was able to get it to engage and we drove in (once again running fine at high rpm).
After coming in i checked if my injectors were firing normal and they seemed to be spraying fine. So i kinda ruled out the lack of fuel there. The next thing i went to was my distributer cap....i seen my contacts were corroded a bit so i shined them up a bit and figured that this had to be the problem. Corroded points not putting enough power to the plugs. So we dipped it back into the lake again and nope..........still nothing. It would only fire on throttle and didn't want to idle.* So now today after more reading i found a few forums with a couple guys who have similar problems as i do. I checked my exhaust shutters and they seem fine, i also have had the battery charger on my battery all day (not to mention) a new battery from last year......so im not sure if that could be it. I fired up the boat not long ago hoping perhaps it was the weak battery and it started right up and for a brief couple seconds it idled strong at 1000rpm on muffs, but then quickly went down to 700rpm and would lope and sound like it would want to die. So im completely stumped!? Whatever happened it all started from that weird wave i caught, it cant be fuel because it seems like my injectors are working 100%.......im thinking it has to do with spark or lack of!?! But would definitely like to hear what anyone else thinks! I would like to get this problem fixed and also save myself the few bucks not taking it into the shop.
