Spark Plugs

[clayinaustin]

I have a 31-foot Cigarette Bullet. It is powered by twin 502cuin engines with Holley 4-barrel carbs. I want to install new spark plugs.

Any suggestions?

 

[old377guy]

Clay, I so wanted to make a smart alec remark about Bullet/bullets; just not witty enough today. Are you tending to foul your plugs and go a heat range higher?

 

[clayinaustin]

Are you tending to foul your plugs and go a heat range higher?

No, I still have my 150 degrees thermostats. My port engine won't idle well and I'm due for some new plugs, so I was wondering what everyone else uses.

The guy at the automotive parts store had no idea what I needed. ;-)

 

[fund razor]

Delco MR43T
or
Champion RV15YC4

Gonna need 16.

There's a chance you are gonna need 2 exhaust manifold gaskets too.
Good luck.

 

[fund razor]

Just saw your post.

Has the port carb been checked out?

 

[clayinaustin]

Thanks Fund! :cheers2:

I've had problems this year with my carbs, but I think they are OK now. I plan to spray some carb cleaner in it, but the new plugs can't hurt!

 

[clayinaustin]

So, two of these?

SPARK PLUG AC DELCO, Pack of 8

 

[Buoy]

Clay, isn't your boat an early to mid '90s?
How many hrs on those motors?
I'm not suggesting rebuilds, but a freshen up on the carbs is cheap (relatively speaking).
Might be cheap insurance/maintenance.
I'm sure you could have it done in a day and be back on the water.

 

[clayinaustin]

Yes, the boat is a 1990, but the engines are 2002 HP500s. Without going into too much detail, I replaced a float on each carb this year and then replaced the base plate on each carb. So, at the time I cleaned them and installed new gaskets. The Starboard engine idles perfectly, but the Port engine won't. I put new spark plugs on the Starboard engine a few years ago, but didn't replace the sparkplugs on the Port engine. So, I want to spray some carb cleaner into the port engine and replace all 16 spark plugs.

I'm no mechanic, but I'm a good parts replacer! ;-)

 

[Buoy]

I'm no mechanic, but I'm a good parts replacer! ;-)

I'm about the same
I've never owned a twin, but I would be inclined to do the same work on both motors -need it or not.
We've known each other on the boards for a long time, and I get the impression you don't run the boat to the max or beat it hard.

Buy the 16 plugs, 2 cans of carb cleaner, some neosporin, and some band aids.
You WILL bust your knuckles

 

[Ratickle]

You also need to check for air leaks around the gasket you replaced on the one engine. If they both were the same, and now one idles great but the other doesn't, could be a simple air leak.

 

[clayinaustin]

You also need to check for air leaks around the gasket you replaced on the one engine. If they both were the same, and now one idles great but the other doesn't, could be a simple air leak.

Neither engine idled very well before I did the work. Now the Starboard engine runs great and the Port engine doesn't. More than one person has told me to install new spark plugs, so I will.

 

[fund razor]

Clay, have you personally done plugs on this boat in the past?

(Reason for asking is that you may have to pull at least one exhaust manifold. Not uncommon, but I have never done a bullet.)

On the carb, is it rich or lean? If neither, throttle stop could have been moved unintentionally.

 

[clayinaustin]

Clay, have you personally done plugs on this boat in the past?

(Reason for asking is that you may have to pull at least one exhaust manifold. Not uncommon, but I have never done a bullet.)

On the carb, is it rich or lean? If neither, throttle stop could have been moved unintentionally.

Yes, I personally replaced the spark plugs on the Starboard side. It was a knuckle buster, but I don't remember removing the manifolds. Also, my engines have some weird custom manifolds, so that may be why I didn't have to remove them.

But you make a good point on the throttle stops. I should probably get a real mechanic to adjust it. In the meantime, I will just replace parts!

 

[fund razor]

Cool. You have it covered.
Since you did the SB, you have your gap also.

Good luck.

 

[bajabob 718]

if you change the plugs and the one motor still run bad. swap the carbs .put the good carb on the bad motor.that will tell you if the carbs bad. did you turn the air mixture screws on the carbs.. turn the in leans them .turn them out rich's them'