On going Engine troubles please help me!!!!

[tryme]

Ok since the beginning of the summeri have battling engine stumbles.  I first thought it was the 20 amp fuse that had a bad connection.  i thought that if i replaced the fuse harness it would fix the issue.  it didnt.  the only thing that concerns me is that the harness i put in is 14 gauge wire and the original wire is 12.  i checked the wire to make sure it wasnt warm.  it checked out fine.  i only have 140 hours on the boat.  a '99 epic 21.  Basically on idle the engine seems to be missing. i am going to check my plugs is it worth replacing them?  if so where can i get them. also does anyone know where i can get a new fuse harness that is 12 gauge wire? 

any other ideas would be great.  any issues with using fuel injector cleaners in the epic?

thanks

mike

[westtx]

Any Toyota or Lexus dealer will have the plugs. Water in the fuel filter could also be getting through if its full. Its probably one of those two and not an electrical issue. Fuel injectors should not be an issue either at 140 hours unless you've put a lot of bad fuel through them. Replace the filter and the plugs and you should be fine.

[tryme]

i just replaced the fuel filter so that shouldn't be it.  ill try the plugs.  would love any other advice

thanks

[toyotafreak]

I think the owner's manual discourages fuel injector cleaners, and also seem to remember Jeff Dorge echoing that. I use Chevron Techron in the Sequoia every 5K oil change, but don't do it in the S22.

Pretty common formula's been repeated here for years: boat runs rough, epicmarine recommends plugs, owner replaces plugs, owner reports back success.

Not sure exactly which wire you're talking about, but the only fused one in mine is the dash computer power supply. The problem with even the stock-size wire is not heating, it's excessive voltage loss which causes low-voltage alarms, etc. at the gauges. Doubt it has any effect on engine smoothness.

[breakawaydaze]

Same problem when I had Wrecks E-21, new plugs, problem gone!

[Rambling Wreck]

As to the plugs, the best price I have found (when shipping is considered) is at rockauto.com. They ship overnight.

DENSO 3297 (SK20R11) Spark Plug $ 9.36 x 8 = $ 74.88
Shipping   $ 5.93
Order Total   $ 80.81

[tryme]

is there any problem using NGK?  rock auto has them for 7.64.   IFR6t11

if not ill order them tomarrow

thanks

[skiboarder]

CHANGE THE PLUGS MINE DID THAT WHEN I BOUGHT IT AND I USED NGK

[Rambling Wreck]

I haven't changed out the Autolites in my E21 yet so I can't give a first hand account but there are many threads here that support the use of Densos. People will have personal opinions of whether they are worth the extra $14.