This is a 1986 Wellcraft Nova II, with two MCM 260, 350" engine in it. It has 2 Perko battery switches which are wired so that on the "ALL" setting the alternator on one engine can charge the other's battery. Yesterday I initially had both batteries set on "1", so neither engine's electrical system could see the other.
The port engine ran fine at first, but after about 45 minutes running about 3500 rpm it gave out. It sputtered and did not want to restart. I did noticed if you gave to too much throttle the RPMs dropped a bit, like it wasn't getting the right amount of fuel when you opened the secondaries, but I backed off the throttle and it perked right up. After moving along with one engine, at about 5mph, for 10 minutes I tried the port engine again and it fired right up and ran fine. I checked the fuel screen in the Quadrajet when we made it to dock and it had a little bit of trash in it, but nothing that would restrict fuel flow.
After reassembling and letting the boat sit for about 30 minutes, we took it back out and the engines performed flawlessly for an 11 mile run down the lake and back, at 40-43 mph. We stopped at an island for a few minutes we needed to go pick up another passenger so I went to fire up the port engine and it didn't want to start. I started the starboard engine and idled away from the island. About 3 minutes later I tried the port engine again and it fired right up and ran fine all the way back to the dock, about 5 miles. We cut the engines off at the dock so passengers could make pit stops and refill coolers then tried to set off again.
This time the port engine did the same thing, not wanting to start at first, but started after the starboard engine was running for a couple of minutes. Once we got out of the no-wake zone and tried to give it some throttle, the port engine sputtered and died. Attempts to restart were fruitless so we idled back to the ramp.
Here's where the electrical system background above comes into play. Once we tied up I tried the port engine again and this time it fired, except the starboard engine cut off. I restarted the starboard engine and the port engine cut off. This went back and forth 5-6 times with me trying to figure out how one engine, with seemingly separate electrical systems could affect the other engine's running.
I switched both battery switches to "ALL", as if the batteries did not have enough juice in them to start one while keeping the other running (I checked bother alternators last week, and both were putting out 14.3-14.4v). Both engines still did the same thing, neither would run at the same time. Again, I stop and discuss this issue with passengers. I then begin trying to start the port engine and get it running again. I try the starboard engine and it fires, but the port engine stays running this time. OK, all's good, let's go back out. We idle out of the no-wake zone, about 1/4 mile, and when I start to give it throttle the port engine dies again. Cannot get it to restart.
Idle back to the ramp again and look down the carb as buddy actuates the throttle. Seems like no fuel. I have a new water sep/filter on board and replace the filter. This is the same engine I checked the screen on an hour ago. New filter/sep in place we fire up the engines and head back out. Don't even get to the end of the no-wake zone before the port engine quits. Head back in to ramp on starboard engine.
Tie up at ramp (this is a private ramp and no one else was around) and fire the port engine. In neutral both engines run 3000 rpm with no problem, but port engine seems like it doesn't want to idle. Run them at various RPM's, up to 3000, while tied to dock, in neutral, trying to figure if there is a fuel flow problem. No problems with engines running now. Let's try going out again. Put the port engine in reverse to back away from dock and it dies. Will not restart. At this point I gave up and put it on the trailer.
Things I plan to check:
1. alternator voltage. at idle and higher RPM.
2. fuel pressure, at idle and higher RPM.
-Both engines have new ignition coils and carbs that were rebuilt last week. While the port engine has a vacuum leak, from wear on the throttle shaft, both engines were running very well on muffs and for some of the time on the water.
-The engine model is MCM 260.
-The fuel seems to come from separate pickup tubes in the tank and go through separate lines to separate water sep/fuel filters for each engine, and there is an additional fuel screen in the Quadrajet.
-I did not feel like either battery had low voltage because they were turning the engines over just fine, even with all the time I spent trying to start them.
All ideas on the various behaviors I saw yesterday welcomed. I'm trying to get this boat right so I can sell it. I don't want to sell no junk.
Thanks,
Chris
The port engine ran fine at first, but after about 45 minutes running about 3500 rpm it gave out. It sputtered and did not want to restart. I did noticed if you gave to too much throttle the RPMs dropped a bit, like it wasn't getting the right amount of fuel when you opened the secondaries, but I backed off the throttle and it perked right up. After moving along with one engine, at about 5mph, for 10 minutes I tried the port engine again and it fired right up and ran fine. I checked the fuel screen in the Quadrajet when we made it to dock and it had a little bit of trash in it, but nothing that would restrict fuel flow.
After reassembling and letting the boat sit for about 30 minutes, we took it back out and the engines performed flawlessly for an 11 mile run down the lake and back, at 40-43 mph. We stopped at an island for a few minutes we needed to go pick up another passenger so I went to fire up the port engine and it didn't want to start. I started the starboard engine and idled away from the island. About 3 minutes later I tried the port engine again and it fired right up and ran fine all the way back to the dock, about 5 miles. We cut the engines off at the dock so passengers could make pit stops and refill coolers then tried to set off again.
This time the port engine did the same thing, not wanting to start at first, but started after the starboard engine was running for a couple of minutes. Once we got out of the no-wake zone and tried to give it some throttle, the port engine sputtered and died. Attempts to restart were fruitless so we idled back to the ramp.
Here's where the electrical system background above comes into play. Once we tied up I tried the port engine again and this time it fired, except the starboard engine cut off. I restarted the starboard engine and the port engine cut off. This went back and forth 5-6 times with me trying to figure out how one engine, with seemingly separate electrical systems could affect the other engine's running.
I switched both battery switches to "ALL", as if the batteries did not have enough juice in them to start one while keeping the other running (I checked bother alternators last week, and both were putting out 14.3-14.4v). Both engines still did the same thing, neither would run at the same time. Again, I stop and discuss this issue with passengers. I then begin trying to start the port engine and get it running again. I try the starboard engine and it fires, but the port engine stays running this time. OK, all's good, let's go back out. We idle out of the no-wake zone, about 1/4 mile, and when I start to give it throttle the port engine dies again. Cannot get it to restart.
Idle back to the ramp again and look down the carb as buddy actuates the throttle. Seems like no fuel. I have a new water sep/filter on board and replace the filter. This is the same engine I checked the screen on an hour ago. New filter/sep in place we fire up the engines and head back out. Don't even get to the end of the no-wake zone before the port engine quits. Head back in to ramp on starboard engine.
Tie up at ramp (this is a private ramp and no one else was around) and fire the port engine. In neutral both engines run 3000 rpm with no problem, but port engine seems like it doesn't want to idle. Run them at various RPM's, up to 3000, while tied to dock, in neutral, trying to figure if there is a fuel flow problem. No problems with engines running now. Let's try going out again. Put the port engine in reverse to back away from dock and it dies. Will not restart. At this point I gave up and put it on the trailer.
Things I plan to check:
1. alternator voltage. at idle and higher RPM.
2. fuel pressure, at idle and higher RPM.
-Both engines have new ignition coils and carbs that were rebuilt last week. While the port engine has a vacuum leak, from wear on the throttle shaft, both engines were running very well on muffs and for some of the time on the water.
-The engine model is MCM 260.
-The fuel seems to come from separate pickup tubes in the tank and go through separate lines to separate water sep/fuel filters for each engine, and there is an additional fuel screen in the Quadrajet.
-I did not feel like either battery had low voltage because they were turning the engines over just fine, even with all the time I spent trying to start them.
All ideas on the various behaviors I saw yesterday welcomed. I'm trying to get this boat right so I can sell it. I don't want to sell no junk.
Thanks,
Chris
