Timing issue?

[hawkinator4]

Hi everyone, I am having a problem with my 98 chaperal I just replaced my cap and rotor and put new spark plugs in. Now when I give full throttle it starts off strong for about two seconds and then lacks so much power that I am only able to get up to 30 mph at about 3000 rpm if I?m lucky and I?m the only one in the boat with passengers I?m good for 15 mph and 2200rpm it also drinks the gas down a lot faster than normal any ideas? The engine number is olo84139 it is a 4.3L mercruiser with the 2 barrel carb. could it be timing?

 

[Bondo]

Re: Timing issue?

Ayuh,... My 1st thought is you have a fuel delivery issue,...

If changing the filter don't help,...
Go up to the Adults Only section,+ observe the listing titled Can't get to WOT...

 

[ziggy]

Re: Timing issue?

so were you trying to fix some issue you had with the new cap and rotor and plugs? or was it just pm. did you gap the new plugs? just changing the cap and rotor shouldn't change timing..

a long shot, doubt this is your problem. but i had a problem when i changed cap and rotor this year. dummy me, didn't tighten one side of the cap all the way down. the result was no secondary fire, no run. the new rotor center terminal had got bent over from the cap being on crooked, hence no complete circuit to the center terminal of the cap as a result of my error. only reason i state this is because it's easy to make a simple mistake, even if you've change lots of caps and rotors before... the simple stuff can come to haunt me...

 

[Don S]

Re: Timing issue?

I just replaced my cap and rotor and put new spark plugs in. Now when I give full throttle it starts off strong for about two seconds and then lacks so much power

Sounds as if you are saying this started after changing the parts. If that is the case, I would suggest you check the firing order of your spark plug wires you may have crossed a couple of wires.

 

[hawkinator4]

Re: Timing issue?

Thanks to you all who have given ideas. But yes it started after the new cap and rotor where put in I have bubble and triple check the firing order as well. I have recently rebuilt my card to but I did take the boat out after I did that and it worked great. I have also just replaced my water fuel separator two trips ago. As for the spark plugs the mechanic I talk to about them had told me that they where pre gaped.

 

[ziggy]

Re: Timing issue?

As for the spark plugs the mechanic I talk to about them had told me that they where pre gaped.

they're not pre gaped. maybe they came right out of the box, maybe they didn't. the proper plugs for my boat, which get R&Red every year, have never been gaped proper for my engine out of the box, year after year.... i always have to re gap them proper myself..

as for the problem at hand. i'd be sure your electric side is up to date and proper. then the fuel system seems to be a likely suspect. but be sure the minor tune up is proper 1st for sure.. then i'd suspect fuel. carb.?

 

[hawkinator4]

Re: Timing issue?

Ha ha sorry everyone I meant carb not card. The boat only has 190 hours on it so I find it hard to think that it is the fuel system. However I really don?t think this would have done it but the last tank of gas that was in it was 100 octane fuel with led in it. Wood that mess up the water fuel separator?

 

[a70eliminator]

Re: Timing issue?

If this happened after changing plugs and rotor than you did either pull a wire off it's connector in the plug boot or mixed up the fireing order cracked the cap or something, the cap set down nice on it's tabs right? the little carbon tip that contacts the rotor didn't fall out did it? Is there a chance you coud have knocked the throttle cable loose during your work and now your carb isn't opening to full throttle? speculatiuons thats all.

 

[hawkinator4]

Re: Timing issue?

The firing order is correct. Although I will check if I pulled I wire out of the boot. What are the chances that the shop I bought the cap and rotor from gave me the wrong cap or rotor or both? After saying this I am going to try putting the old cap and rotor back on and see if that fixes the problem.

 

[Don S]

Re: Timing issue?

It's a thunderbolt V ignition system. The only way they could have given you the wrong parts is if the cap had 8 posts for spark plug wires, or 8 slots in the rotor.
If either was the wrong part, I don't think it would even run. If it did run, it would sound horrible, even at idle. If you could get it to idle and not backfire like crazy.

 

[hawkinator4]

Re: Timing issue?

great news i got it figured out the cap was cracked, now it runs like a champ.

 

[bhammer]

Re: Timing issue?

but the last tank of gas that was in it was 100 octane fuel with led in it. Wood that mess up the water fuel separator?

Glad you got it fixed. Why are you running 100LL in boat? Have extra from the airport or something? The 100LL at the airport is always more expensive than the best auto gas money can buy.

 

[hawkinator4]

Re: Timing issue?

Lol not when you are working in the hanger as a mechanic. After we drain the tanks we can?t by regulation put it back in so what ells to do with it then run it in the boat yea know. So yes if I was paying for it, it would be much more then premium at the gas station.

 

[bhammer]

Re: Timing issue?

I used to run it in an old pickup truck that didn't have O2 sensor or catcoverter. I think those are the only two components on an auto engine that would be affected by the lead. I got mine the same way, after sumping tanks and repairs.... Now, when I have extra Jet A, I run it in our tugs. Had about 50 gal one time and had a buddy that bought it for $50 and ran it in his truck. Always asks if I have more now.....

 

[hawkinator4]

Re: Timing issue?

Yea it?s a nice place to be in when tanks get drained. But on top of the two things you mentioned the valve guides get eaten up by it also in the new motors because they aren?t lubricated, but no besides that if it is an older motor without all the computers it normally works great! So are you a pilot to or just worked in a hanger?