ive been trying to get both engines synced, or close in operation since buying the boat. just recently ive had the rave valves out and cleaned on a wire wheel, all 4 carbs off, gone through, cleaned, reinstalled, new plugs and fresh gas. my stronger of the two engines that normally kicks up to 7k quicker (prob because wear ring worn) is stumbling, and my other engine that seems to top out around 6500rpms is doing the majority of the work. after all this work mentioned above i had the boat out on the water and it ran pretty darn good. put a solid hours worth of riding around at 3/4-wot with plenty of messing about in between. boat ran great up until the time it was out of the water. the only thing i didnt do was turn the gas off at the knobs under the engine compartment cover. well took the boat out yesterday and as stated the one engine wouldnt rev past 4500rpms. i checked spark, seems to be consitant and strong with both plugs grounded to engine. i also cut back the plug wires and reinstalled the plug boot just in case there was corrosion but i didnt see any. i turned the gas off, ran the gas out of the carb, then turned the knobs back on and did a lake test with new plugs and same thing. what can i check? when i pull the plugs they seem wet and black. the boat doesnt smoke abnormally, only at startup. both engines fire\start pretty easy cold or hot, but you can hear the one missing and they are even different rpm's at idle (both levers all the way down) any ideas? all 4 cylinders are 150psi, rave valves are cleaned and the newer version with slots.
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twin 787s in challenger, one not reving out past 4500rpms
- Thread starter mxracer32
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no its doing this while driving the boat on the lake, lever def. in forward. ive been searching and found something about a rev limiter switch going bad on the lever control unit that kicks in the rev limiter. would that only affect one engine since it has two levers, or is there seperate switches for each engine?
yes its only one engine. i guess i will pop that mag cover off. im still waiting for my manual. hopefully it will get here today since i dont know what that pulse coil looks like. im assuming its a magneato type pickup behind the cover?
yes its only one engine. i guess i will pop that mag cover off. im still waiting for my manual. hopefully it will get here today since i dont know what that pulse coil looks like. im assuming its a magneato type pickup behind the cover?
smartbuffboy
New Member
similar problem with rev
I'm having a similar problem where one engine will rev, the other will not. Recently took off a broken shaft cover on that engine due to cavitation, now does not cavitate. I left a little bit of it there to provide a "seal" between the shaft and engine compartment. Would this cause issues with the rev on that engine, I can't think of why it would, but thought I'd ask.
Also, how exactly does the rev limiter work, is it expensive to replace, is it something I can do myself, and how do I know for sure that this is the problem?
Thanks!
Richard.
I'm having a similar problem where one engine will rev, the other will not. Recently took off a broken shaft cover on that engine due to cavitation, now does not cavitate. I left a little bit of it there to provide a "seal" between the shaft and engine compartment. Would this cause issues with the rev on that engine, I can't think of why it would, but thought I'd ask.
Also, how exactly does the rev limiter work, is it expensive to replace, is it something I can do myself, and how do I know for sure that this is the problem?
Thanks!
Richard.
:banghead:
tore into the boat yesterday. checked electrical box first, all fuses good, rechecked plug wires, lever assembly, couldnt find any problems, so i decided to pull the rave valves again. apparently i got some bad info on rave valve installs. had all 4 turned the wrong way. wow. thats about all i can say. i should just keep quiet and tuck my tail between my legs but hopefully someone will find this post and recheck theirs if they are experiencing similar problems. did a water test and one engine tach'd up instantly, the other bogged down. swapped plugs with some others i had and it did the same thing. then i swapped the plugs between the two engines and the problem followed the spark plugs, so out of 8 NGK br8 plugs, i had 2 that are bad and i managed to put one in the same motor each time wtf...i raced dirtbikes for years, only used NGK's and cant say ive ever had a bad one from the factory (as in small crack in porcelean, arc jumping, etc) maybe this bunch was dropped during shipping or something. anyways, changed them out and W O W. it runs like its suppose to, damn its fast. the lake was like glass last night, no other boats, no wind, no current. speedometer hit 61mph with me in it. the first day i got the boat i hit 50 on the speedo and my gps said 48. i didnt have the gps with me this time but i would have to guesstimate a true 55-58mph. i wasnt expecting that, i had the bimini top up too, oops. maybe i'll get a few more mph with it down. damn this thing rips. enough with this tinkering, time to enjoy the boat for the last couple months of summer. :hurray:
tore into the boat yesterday. checked electrical box first, all fuses good, rechecked plug wires, lever assembly, couldnt find any problems, so i decided to pull the rave valves again. apparently i got some bad info on rave valve installs. had all 4 turned the wrong way. wow. thats about all i can say. i should just keep quiet and tuck my tail between my legs but hopefully someone will find this post and recheck theirs if they are experiencing similar problems. did a water test and one engine tach'd up instantly, the other bogged down. swapped plugs with some others i had and it did the same thing. then i swapped the plugs between the two engines and the problem followed the spark plugs, so out of 8 NGK br8 plugs, i had 2 that are bad and i managed to put one in the same motor each time wtf...i raced dirtbikes for years, only used NGK's and cant say ive ever had a bad one from the factory (as in small crack in porcelean, arc jumping, etc) maybe this bunch was dropped during shipping or something. anyways, changed them out and W O W. it runs like its suppose to, damn its fast. the lake was like glass last night, no other boats, no wind, no current. speedometer hit 61mph with me in it. the first day i got the boat i hit 50 on the speedo and my gps said 48. i didnt have the gps with me this time but i would have to guesstimate a true 55-58mph. i wasnt expecting that, i had the bimini top up too, oops. maybe i'll get a few more mph with it down. damn this thing rips. enough with this tinkering, time to enjoy the boat for the last couple months of summer. :hurray:
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