83 Mercruiser 470 Bogging Out After 45min

[HEINOT]

We had a problem with the motor bogging out at higher rpm's. Found dirty fiter and replaced filter w/new fuel filter/ water sep. Took boat out ran good for 45 min. then started bogging at higher rpm's. Then we rebuilt carb. took it out same thing. Starts good 45 min. later it boggs out. Changed fuel lines, ck'd vent line to tank, ck'd pick up tube everything clean. it starts up at the begining of every trip but 45min to an hour it starts bogging out. Anybody have any suggestion?

 

[Friscoboater]

Re: 83 Mercruiser 470 Bogging Out After 45min

I have the same thing happening to my boat. I am thinking I have an ignition problem.

 

[Don S]

Re: 83 Mercruiser 470 Bogging Out After 45min

http://forums.iboats.com/showthread.php?t=283269

 

[Friscoboater]

Re: 83 Mercruiser 470 Bogging Out After 45min

Conpression is great. It sounds like a miss, and it runs fine sometimes. Seems to be surging. To me it sounds like an arching plug wire.

 

[Friscoboater]

Re: 83 Mercruiser 470 Bogging Out After 45min

also new fuel pump and filters

 

[jrtredo]

Re: 83 Mercruiser 470 Bogging Out After 45min

Could be trash in your gas tank getting sucked up in the pick up. Maybe the went on your gas cap isnt working and pressure builds up after a while and makes the trash easier to pick up.

 

[solar7647]

Re: 83 Mercruiser 470 Bogging Out After 45min

I had this issue also. In my case what it was, was bad sparkplug wires. The boat would run great until it was hot, then when I would go to high RPM it would drop out because the wires would get warm and start sparking off the manifold. I would recomend changeing the wires then trying again. If you dont want to just get new wires, start the engine and let it get to operating temp (160) Then slid your hand over the wire, it will only hurt for a sec. Unless you know of a faster/better way to check it. Like I said it was only happening to me when hot, once the rubber on the wire got hot a bunch of cracks showed up.

Good luck

 

[jul3z]

Re: 83 Mercruiser 470 Bogging Out After 45min

Resurrecting an old thread, but for the sake of safety I suggest taking a spray bottle, setting it to mist and spraying the plug wires with it. If you're in a dimly lit area or cut the lights, you will be able to see the spark arcing off the cables. No need to get yourself shocked.