Loss of power/engine coughs then dies
06-28-2010, 02:40 PM
#11
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Do you have the Thunderbolt Rev Limiter?
I just had one that would do something similar. When it was cold it would run fine, start right up, we could run it no problem for about 20 mins. Then it would sputter and die. First couple times it would start back up then it got to the point where it would have to sit overnight before it would start. Left us stuck with one motor about 20 miles from the dock TWICE.
For some reason, we only had the rev limiter on one motor so I moved it to the other one, problem followed the rev limiter so I cut the harness apart to bypass it, motor fired right up. I just tried to get the correct bypass harness from BAM but its NLA so I'll just permanently solder the splices in and leave it be.
A handy way to see if you are definitely not getting spark is to use a ty-wrap to keep the trigger on your timing gun in, then when the motor dies hook your timing gun up and see if you are getting spark for sure or not. Probably not. Just put the gun where you can see it flash while trying to crank.
I just had one that would do something similar. When it was cold it would run fine, start right up, we could run it no problem for about 20 mins. Then it would sputter and die. First couple times it would start back up then it got to the point where it would have to sit overnight before it would start. Left us stuck with one motor about 20 miles from the dock TWICE.
For some reason, we only had the rev limiter on one motor so I moved it to the other one, problem followed the rev limiter so I cut the harness apart to bypass it, motor fired right up. I just tried to get the correct bypass harness from BAM but its NLA so I'll just permanently solder the splices in and leave it be.
A handy way to see if you are definitely not getting spark is to use a ty-wrap to keep the trigger on your timing gun in, then when the motor dies hook your timing gun up and see if you are getting spark for sure or not. Probably not. Just put the gun where you can see it flash while trying to crank.
Last edited by c_deezy; 06-28-2010 at 02:47 PM.
06-28-2010, 06:06 PM
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freind of mine had similar issue after a season of replacing everything he could he took to mechanic only to find a partialy kinked fuel line, it would actually close then after it would cut out it would restart and do the same thing again. rerouted and replaced line and hasn't missed a beat
06-28-2010, 11:13 PM
#16
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Fixx
changed the coil, took it out this morning...same damn thing, starts right up, gets on plane, drive around for 5 minutes, come back to marina, start to slow down, as rpms drop below 2600 rpm, cough/spit, push throttle down, smooths out and stays running...then slow down again, engine cuts outs out. starts back up for 30 sec, idling, now I can't get it started again...pull off flame arrestor, carb is wet looking. its always started back up before. Luckily the wind blows me the last 50 yds to dock. Back in slip after 15 min, it starts back up, but dies in about 5 sec.
06-29-2010, 10:45 AM
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just came back from the boat with mechanic down there. I finally broke down and had someone come out. Now the boat won't even start...As I cranked the mech noticed spark arcing where the main plug wire attaches to the coil.
I never noticed it before because at the helm you can't see behind the coil.
He tested the wire and sd it had a lot of resistance. He's getting a new wire and we'll see if that solves it. No spark is getting to the plugs!!! I hope this is it.
I never noticed it before because at the helm you can't see behind the coil.
He tested the wire and sd it had a lot of resistance. He's getting a new wire and we'll see if that solves it. No spark is getting to the plugs!!! I hope this is it.
06-29-2010, 06:23 PM
#18
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New plug wires and and plugs fixed ign issue...but now mechanic reports low/no compression on cyl 4&6. So he tells me to call engine builder and ***** at him, suspects blown head gasket. Engine only has 3 hrs on it and never ran hot. Engine builder says to doublecheck valve asjustments, valve could be hanging open. Mechanic acknowledges he should have popped valve cover off and checked it before he left. Going back tom AM to check valves...So I'm over $6k, did the install myself, and still don't have a working boat!!
