defective distributor caps?

j_reed

Cadet
Joined
Oct 8, 2009
Messages
24
I replaced the cap and rotor on my searay over the winter and first time out on the lake it seems to idle fine, but when I added throttle after the engine is plenty warm it bogs and coughs a little, feathering in the throttle it takes off and seems to run fine. when I shut is off and try and restart, it doesn't want to, engine turns over, it just doesn't want to catch, for the most part this boat has always started reliably (though little harder when warm) if eventually starts but not easily, I also notice that the idle is pretty low, I started wondering if I should have checked/reset the timing? though really I shouldn't have to right? while researching on internet is seems that there were a number of bad distributor caps produced by mercruiser as well as sierra in 2011. any experiences like that? this cap set is from napa which I assume is sierra. my other thought is the carb might need another rebuild? and the problem has surfaced over the winter, its been 6 years I think, though the boat has not had a lot of hours in that time, maybe 60-70 in total if that matters.
thanks for any help guys
great forum.
-jay

1995 searay BR195
4.3 2bl carb
 

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
Re: defective distributor caps?

How fresh is the gas?
 

Bt Doctur

Supreme Mariner
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Aug 29, 2004
Messages
19,093
Re: defective distributor caps?

You did nothing else all winter and just changed the cap this seeason? What about the required maintance ?
 

Watermann

Starmada Splash of the Year 2014
Joined
Jan 12, 2013
Messages
13,747
Re: defective distributor caps?

Bad cap would make the engine mis, sounds to me like a fuel delivery problem. Also doing a half way tune up isn't the best way, I always give my motors the full meal deal, cap, rotor, wires and plugs. If the motor's older, there's also the ignition module or points & condenser as well.
 

j_reed

Cadet
Joined
Oct 8, 2009
Messages
24
Re: defective distributor caps?

fuel is new, I added sabil and fogged, properly winterized last fall. its electronic ignition, thunderbolt iv I believe, idle was down about 200 rpms this year, I wondered if it was the cap because its the only thing thats changed. I personally think that changing spark plugs and wires on high voltage system is overkill and that they last a long long time. this became apparent to me when I changed the plugs in a mini van I used to have (also a 4.3), they still had the factory motor paint on them at 175,000, I not sure it even ran better after. -j

1995 searay BR195
4.3 2bl carb
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: defective distributor caps?

If you still have the old cap and rotor, put them back on and see if the problem disappears... If it does, you know what to do.. If the problem persists, clean out the carb, change ALL the filters and fill the tank with FRESH fuel....

Chris........
(P.S. This is why I never throw away old parts (unless they are broken) until I have confirmed the new parts are working properly)....
 

Watermann

Starmada Splash of the Year 2014
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Messages
13,747
Re: defective distributor caps?

So what problem was there to cause you to change the cap and rotor? Recheck the firing order and re-seat the wires.
 

j_reed

Cadet
Joined
Oct 8, 2009
Messages
24
Re: defective distributor caps?

I will try the old cap again, the old rotor broke apart trying to remove it... that locktite sure works well. I replaced them because at ski speed (4000 rpms) the engine seemed to surge a little, maybe a couple hundred rpms up and down, I'm not sure you could see it on the gauge but you could feel it/hear it just slightly, I thought maybe it was the cap/rotor and it had not been changed in a while. thanks again for the help. -jay

1995 searay BR195
4.3 2bl carb
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: defective distributor caps?

In my experience with the V6s (which is actually quite a lot :D ;)), surging usually means it's asking for new spark plugs....

Chris....
 

j_reed

Cadet
Joined
Oct 8, 2009
Messages
24
Re: defective distributor caps?

well I couldn't located the old cap to try and go back to it.... I thought for sure that I saved it, but anyway... I checked the timing and it was way off. am I crazy? a different brand of cap should not have affected timing should it ? the timing being off was my initial thought when the idle was so different, anyway, adjusted timing, readjusted idle. seems to be running fine. thanks guys. -jay

ps that tiny bit of surge is still there, the reason I changed the cap in the 1st place, you can in-fact barely see it on the tach, maybe 25 rpms up and down while cruising at 3500 rpm's. "achris" said to change spark plugs, they are not easy to get at and you have to remove the molded rear fiberglass seating to accomplish it. will see. -j

1995 searay BR195
4.3 2bl carb
thunderbolt iv
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: defective distributor caps?

.... to change spark plugs, they are not easy to get at and you have to remove the molded rear fiberglass seating to accomplish it. will see.

Yes, you could change everything else that's easy to get at, but that's not going to fix the problem if it's being caused by something 'not easy' to change...

Get use to removing those seats by the way... .Usually the first thing you'll be doing when something starts playing up is to pull the spark plugs and either replace them, or do a compression test... Both of which should be done on the annual service anyway....

Chris......
 
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