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Hello,
Background
I have twin 2002 F200’s on a 28’ Grady White. I bought the boat last year and while it ran good I knew I needed to do the midsections. This March I did both midsections as well as all of the anodes (internal/external), thermostats, fuel filters, plugs, lower unit fluid etc.. The motors have been running great and I have put 100 hours on them since these updates.
While I purchased new VST filters, the local Yamaha shop said if they were running well, leave those alone so I did not mess with them.
Problem
Fast forward to this Friday, we ran 80 miles east to the Norfolk Canyon, cruising 4400 rpm, 30 mph ran like a dream. We *****ed for about 4 hours and decided to run in closer to a new spot. On the way out I ran the aux tank, while *****ing I switched to the main fuel tank. Powered up and began running same rpms then the PORT motor fell off to about 3500 rpms and was making a popping sound, like a misfire so I backed it down to idle and it idled rough and was shaking as the rpms went from 400-800 erratically. Tried to rev and more popping. I remembered switching tanks and thought maybe I had gotten some moisture, though both tanks filled at the same time and fresh fuel.
I removed the port fuel water separator and emptied it, put it back on and got back to cruising speed for a few minutes before repeating the process, it continued to get worse each time, then I also tried draining the vst and on engine fuel filter along with the separator and was able to get to cruising speed 1 or 2 more times. I also swapped the fuel water separators to see if that one filter was it, and the same thing happened, still only on the PORT motor. After all that, it would only run about 2200 rpms smoothly so we settled on that and limped in from 65 Miles out.
Since the fuel water separator seemed to make an initial difference, I am thinking fuel starvation and the VST filter is likely clogged, although it could be an injector too I suppose. Pumping the primer bulb did not help, and the VST tank is filling each time so the low pressure lift pump must be working. One weird thing I noticed a few weeks ago, I tilted that motor all the way up and some fuel ran down out of the cowling, which i thought was strange but it ran fine so I thought it was an anomaly. I've read something about the VST float needle being dirty could allow this to happen but not sure this is tied to the overall issue (other than dirty VST chamber which could leave both the needle and filter riddled in filth/deposits).
Yesterday I went to clean the boat and did not start either motor, but I did hookup my laptop to see if there were any codes from the day before. That motor had code 29 intake pressure and 45 shift cutoff switch. I have read Rodbolt's explantion of how misfire/backfires through the intake can certainly throw a code 29 so that could make sense. The only weird thing about the static download was the atmospheric pressure on the PORT motor with engine off is off. The STBD motor showed 29.6 atmospheric and 29.8 intake pressure (which is the pressure here yesterday). The PORT motor showed 31.6 atmospheric and 35.94 intake pressure. Neither motor had been running for 12 hours, completely cold.
While researching I read an old thread Rodbolt helped a guy also with an F200. His atmospheric pressure was also off like mine and the ISC ended up being the issue.
I'm sorry for the long post, but I know it never helps to leave out details and am looking for some guidance to see if I'm on the right track.
My first plan of action this week is to clean the VST, replace that VST filter, F shaped filter, on board filter, and fuel water separator and reset the codes and see what happens.
Does that sound like a good first step? The atmospheric pressure being off sounds a lot like that other dude's problem, but I don't want to go buy an ISC for no reason. If the ISC was the only issue, would it still run ok once revved up? If it was stuck I can see how that could throw off the pressure readings (assuming the sensor is ok). I should also check the voltage at the sensor I suppose as well. One more thing, after I did the maintenance in March, I pulled the codes and the code 29 was there but had occurred before I ever bought the boat, and showed normal that day engine not running. However the pressure was not off at that point either (atmospheric and intake pressures were same).
I appreciate any guidance. I have read as many past posts as possible in order to avoid Rodbolt or Boscoe having to repeat the same thing until they're blue in the face, but thought my symptoms were different enough to warrant a new thread.
Thanks for reading and gain sorry for the long post! I attached the YDS info for both motors for comparison but the PORT is the issue at the moment (although the STBD did overheat briefly Friday after trying to run the boat on it alone, trying to run on plane but I realized it was just too much load and it did not like it and didn't feel good for it.
Scott
Background
I have twin 2002 F200’s on a 28’ Grady White. I bought the boat last year and while it ran good I knew I needed to do the midsections. This March I did both midsections as well as all of the anodes (internal/external), thermostats, fuel filters, plugs, lower unit fluid etc.. The motors have been running great and I have put 100 hours on them since these updates.
While I purchased new VST filters, the local Yamaha shop said if they were running well, leave those alone so I did not mess with them.
Problem
Fast forward to this Friday, we ran 80 miles east to the Norfolk Canyon, cruising 4400 rpm, 30 mph ran like a dream. We *****ed for about 4 hours and decided to run in closer to a new spot. On the way out I ran the aux tank, while *****ing I switched to the main fuel tank. Powered up and began running same rpms then the PORT motor fell off to about 3500 rpms and was making a popping sound, like a misfire so I backed it down to idle and it idled rough and was shaking as the rpms went from 400-800 erratically. Tried to rev and more popping. I remembered switching tanks and thought maybe I had gotten some moisture, though both tanks filled at the same time and fresh fuel.
I removed the port fuel water separator and emptied it, put it back on and got back to cruising speed for a few minutes before repeating the process, it continued to get worse each time, then I also tried draining the vst and on engine fuel filter along with the separator and was able to get to cruising speed 1 or 2 more times. I also swapped the fuel water separators to see if that one filter was it, and the same thing happened, still only on the PORT motor. After all that, it would only run about 2200 rpms smoothly so we settled on that and limped in from 65 Miles out.
Since the fuel water separator seemed to make an initial difference, I am thinking fuel starvation and the VST filter is likely clogged, although it could be an injector too I suppose. Pumping the primer bulb did not help, and the VST tank is filling each time so the low pressure lift pump must be working. One weird thing I noticed a few weeks ago, I tilted that motor all the way up and some fuel ran down out of the cowling, which i thought was strange but it ran fine so I thought it was an anomaly. I've read something about the VST float needle being dirty could allow this to happen but not sure this is tied to the overall issue (other than dirty VST chamber which could leave both the needle and filter riddled in filth/deposits).
Yesterday I went to clean the boat and did not start either motor, but I did hookup my laptop to see if there were any codes from the day before. That motor had code 29 intake pressure and 45 shift cutoff switch. I have read Rodbolt's explantion of how misfire/backfires through the intake can certainly throw a code 29 so that could make sense. The only weird thing about the static download was the atmospheric pressure on the PORT motor with engine off is off. The STBD motor showed 29.6 atmospheric and 29.8 intake pressure (which is the pressure here yesterday). The PORT motor showed 31.6 atmospheric and 35.94 intake pressure. Neither motor had been running for 12 hours, completely cold.
While researching I read an old thread Rodbolt helped a guy also with an F200. His atmospheric pressure was also off like mine and the ISC ended up being the issue.
I'm sorry for the long post, but I know it never helps to leave out details and am looking for some guidance to see if I'm on the right track.
My first plan of action this week is to clean the VST, replace that VST filter, F shaped filter, on board filter, and fuel water separator and reset the codes and see what happens.
Does that sound like a good first step? The atmospheric pressure being off sounds a lot like that other dude's problem, but I don't want to go buy an ISC for no reason. If the ISC was the only issue, would it still run ok once revved up? If it was stuck I can see how that could throw off the pressure readings (assuming the sensor is ok). I should also check the voltage at the sensor I suppose as well. One more thing, after I did the maintenance in March, I pulled the codes and the code 29 was there but had occurred before I ever bought the boat, and showed normal that day engine not running. However the pressure was not off at that point either (atmospheric and intake pressures were same).
I appreciate any guidance. I have read as many past posts as possible in order to avoid Rodbolt or Boscoe having to repeat the same thing until they're blue in the face, but thought my symptoms were different enough to warrant a new thread.
Thanks for reading and gain sorry for the long post! I attached the YDS info for both motors for comparison but the PORT is the issue at the moment (although the STBD did overheat briefly Friday after trying to run the boat on it alone, trying to run on plane but I realized it was just too much load and it did not like it and didn't feel good for it.
Scott
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