Distributor?

[Bc197]

I have a 1987 165 hp mercruiser I purchased that hadn't been in water for 2 years I changed plugs points gas lines both fuel filters plug wires and it fired right up and ran great until 2 weeks ago it started back fireing at half throttle I thought bad gas so I drained the tank still back firing . I could get it wide open and it would miss a little so I checked the rotor it had a hole burn thru the center , I then changed the plugs again and the distributor rotor and points it ran great for an hour then stared backfiring again even worse so I pull the cap off and the rotor had broke again and chewed up the inside of the cap. When I pull up on the distibuto shaft it moves about 3/8 of an inch is this to much ? Possible bad cam? Help!

 

[Kainon]

Re: Distributor?

Distributors do have some pay, 3/8" sounds like a lot.. there are specifications for end play somewhere.

the Cam shaft wouldn't have an affect on end play, but where the shaft is riding up and doing damage, somethings going on. I dont see why you couldn't remove it, tap out the roll pin and shim it. (between the dist gear and housing)

New Cap & Rotor right ?

THe spring on the rotor should keep the shaft down.

 

[Silvertip]

Re: Distributor?

Pulling up that far indicates distributor wear, not camshaft wear. If the distributor shaft can be moved even slightly laterally (sideways) that can cause runability issues as the dwell angle and hence timing changes. You did set the dwell and timing after changing the points didn't you? That's a must!!!

 

[EddiePetty]

Re: Distributor?

....... When I pull up on the distibuto shaft it moves about 3/8 of an inch is this to much .....

...I don't believe you are lifting the distributor shaft 3/8". You're probably lifting the points cam and rotor drive off its drive pin and allowing the advance weights to slip under the cam plate, thus causing rotor failures. Remove the rotor, and complete breaker plate assembly and see if the flyweights aren't out of place.

 

[libellav15]

Re: Distributor?

there should be a plate screwed over the 2 weights to stop the rotor drive lifting away and the weights closing up below it.

has the rotor actually come off the cam and destroyed itself then? or is it just burnt through again?

voltage regulator checked?