My Convincor has a miss.

[Superjet]

I have a '98 253 Convincor with a std carbed 454. I have had the boat for about 5 years and it has always run perfect.

This year it developed a weird miss. It did it a couple of times early in the year, but by the end of the year it would do it every 5 to 10 minutes. It only occurs at an idle cruising down the channels at around 1000 rpm. Cruising at speed it is perfect.

It really isn't a miss. It literally totally cuts out like the key or lanyard are pulled for a split second and then it jumps right back to life and runs perfect. It is a very clean and crisp cut where it acts like all 8 cyl. just die for a second.

It's been a few years since I have done a tune up, but it doesn't seem like that is the problem to me.

Any advice?
I was thinking coil or some other ignition issue???

 

[bigsbetter]

Wow...Only once every 5-10 minutes is going to be tough. But at least I think you're on the right track, gotta be ignition, and like you say, primary side, not secondary side if it feels like all 8. Possibly loose wire, or coil. 1000 rpm is pretty slow just enough to make a lil plow and put the engine under some light load.

 

[mkhammer]

I have a '98 253 Convincor with a std carbed 454. I have had the boat for about 5 years and it has always run perfect.

This year it developed a weird miss. It did it a couple of times early in the year, but by the end of the year it would do it every 5 to 10 minutes. It only occurs at an idle cruising down the channels at around 1000 rpm. Cruising at speed it is perfect.

It really isn't a miss. It literally totally cuts out like the key or lanyard are pulled for a split second and then it jumps right back to life and runs perfect. It is a very clean and crisp cut where it acts like all 8 cyl. just die for a second.

It's been a few years since I have done a tune up, but it doesn't seem like that is the problem to me.

Any advice?
I was thinking coil or some other ignition issue???

You may have answered your own Question. A safety kill switch can work intermittently when going bad, check continuity with a ohm meter while pushing in and out. See if it occurs again. Check for loose wires that have to do with ignition and clean terminals everywhere. May fix the problem.

MKHammer

 

[Mr. Buss]

does your motor shut off for a split second when you shift gears??
my senator kinda kicks off for a split second when switing to nuetral .. i think it helps it drop outta gear?? i dunno if all boats do something like this??

it might be something in that switch/safety/ cutoff mechanism as mkhammer mentioned??

good luck!!

 

[Superjet]

does your motor shut off for a split second when you shift gears??
my senator kinda kicks off for a split second when switing to nuetral .. i think it helps it drop outta gear?? i dunno if all boats do something like this??

it might be something in that switch/safety/ cutoff mechanism as mkhammer mentioned??

good luck!!

Actually I was talking to someone else that also suggested this. That could definitely be the problem. I guess there is a switch that kills it for a split second when it goes into gear. I can't say I ever noticed it when shifting, but it makes sense.

I'm pretty sure it isn't a loose wire because then I think it would be acting up even worse while bouncing around at speed.

I thought about trying a coil since they are a cheap place to start if I don't find anything else.
The trouble is, the boat is tucked away for winter so I won't know if I have it fixed until spring

 

[bigsbetter]

The shift interupt switch should be located on the bracket on top of the engine where your throttle and shift cables go. It rocks back and forth when you shift to cut out the engine for just a split second to help it shift.

 

[Superjet]

The shift interupt switch should be located on the bracket on top of the engine where your throttle and shift cables go. It rocks back and forth when you shift to cut out the engine for just a split second to help it shift.

I just talked to my local Checkmate dealer and they said I don't have a shift interupt on my 454/bravo 1.

 

[happy]

your problem is in the distributor wiring harness directly related to your amplifier. Say amen.. This lil problem whipped my butt a couple of times.. never again!@!.. I drove a cigarrette for 70 miles before I stopped dead in the houston ship channel because of this.. And if I'm wrong your loss will be 10 bucks and 2min.

 

[Lakeside Restorations]

It could be what has already been mentioned, Or you may also have a fuel problem. You may have moisture in the fuel, or Debris that intermitantly blocks the fuel pick up off. It is strange that it happens like it does, but not under more load. It may even be a out of adjustment carb or choke set up.. Good luck in your quest.. Jamie / Lakeside

 

[ezstriper]

also pull the big main wiring connector apart ck for corrosion or sings of poor contact in there...had that happen before....sometimes you can go and wiggle it with the engine running and see if it stalls/changes good luck Rob

 

[Superjet]

your problem is in the distributor wiring harness directly related to your amplifier. Say amen.. This lil problem whipped my butt a couple of times.. never again!@!.. I drove a cigarrette for 70 miles before I stopped dead in the houston ship channel because of this.. And if I'm wrong your loss will be 10 bucks and 2min.

The dealer I talked to said there is a pick up under the rotor. Sounds like you guys are pointing the same direction. I think I will take a look at that tomorrow.

I was going to run across Lake Michigan to Chicago over Labor Day weekend, but I really didn't trust it. Didn't want to get 40 miles from land and have it quit.

As crisp and clean as it cuts out I am really leaning toward electical more than carb/fuel related. It could be an ign. switch or teather related thing, but I would think that would happen when cruising at speed as well.

 

[Superjet]

your problem is in the distributor wiring harness directly related to your amplifier. Say amen.. This lil problem whipped my butt a couple of times.. never again!@!.. I drove a cigarrette for 70 miles before I stopped dead in the houston ship channel because of this.. And if I'm wrong your loss will be 10 bucks and 2min.

So it I should look at the actual amplifier or just check wiring harness and connections?
I am pretty handy, but have never dug any dealer than cap/rotor/wires on anything 4 stroke.

 

[winter]

As mentioned before, because you have a cone-type clutch in your drive, there is no need for an momentary ignition kill switch. I can't begin to tell you all the trouble i had with my boat this year, as i to had a miss i couldn't find. Simply put, unless you have the time to replace one part and drive it for awhile, then replace the next part etc... you might just want to replace some of the common failure parts right off the bat. Cap, rotor, wires, plugs then you have a good tune-up out of the way. The ignition amp is possible (on the port side manifold) but not as likely as the dist. pick-up or coil. other than that, check your wiring very carefully.