3.0LX No Start Problems on New Purchase Boat

[lilboatsman]

It's a boat I purchased recently with a 3.0LX, and I just got it cranking with a new starter. When I add a little gas to the carb, it backfires a little, but doesn't act like any motor that wants to start.

Here's what I've figured out so far:
-Plugs look fairly new
-firing order is correct (1,3,4,2 turning clockwise)
-I'm getting spark on all 4 cylinders
-Added gas several times to the carb, every time it just backfires a little when I crank it.

I've thought about doing a cap and rotor, but it seems like it must be something more than this when I'm getting spark.

Maybe there is an exhaust flapper that's stuck closed? Any ideas?

 

[bruceb58]

Has it ever run? Have you ever removed the distributor?

 

[tpenfield]

Ignition timing . . .

When you say 'new' I assume that you mean new-to-you

 

[lilboatsman]

I've never had it run, it wasn't running when I purchased it a week ago. I've never pulled the distributor. I'll try turning the distributor a little bit here and there to see if anything happens. If not, then I'll pull the #1 plug and do it properly.

 

[s.hadley81]

I think a compression test might be a good idea that will tell you a little more about the health of the motor.

 

[enginesilo]

Yup compression test would be a good start. Since it wasn't running before it could be almost anything from an electrical/timing issue, to fuel delivery/carb, and beyond. See if compression is even or nearly the same across all cylinders to start.

 

[Scott06]

In addition to compression test . Check the spark by grounding a plug should have a nice blue spark, if not diagnose ignition system. Would also check timing with a timing light while cranking the engine to make sure your in the neighborhood. A backfire is indicative or incorrect timing, as you should get something resembling running if the igntion is correct and you dump gas down carb.

 

[lilboatsman]

Timing was the culprit. I finally pulled plug one and figured it out. Thanks for everyones help.

Now about the compression test, I've never done one before. Is it as simple as getting one of those gauges that screw into the plug hole?

 

[tpenfield]

Timing was the culprit. I finally pulled plug one and figured it out. Thanks for everyones help.

Now about the compression test, I've never done one before. Is it as simple as getting one of those gauges that screw into the plug hole?

Pretty much . . . You will want to run the engine up to operating temperature before doing the test. Keep a battery charger going on the battery, so that it does not run down (less of an issue with only 4 cylinders). Pull all of the spark plugs. you might want to disconnect the coil wire from the distributor and ground it somewhere, so you are not throwing sparks all over the place. Connect the pressure gauge to a spark plugs hole (make sure you have a gauge that is for compression testing, as it has a check valve with a pressure release). Give each cylinder 5-6 compression strokes of 'cranking' with the starter and record the reading on the gauge. Then move onto the next cylinder. Your compression should come up after about 2 compression strokes during the 'cranking' of the engine . . . the few extra compression strokes are just for good measure.

 

[bruceb58]

you might want to disconnect the coil wire from the distributor and ground it somewhere, so you are not throwing sparks all over the place

Pulling the man overboard switch, if you have one, is also a good way to disable the spark.

 

[nola mike]

...and put the controls at WOT. I think there's a sticky somewhere...

 

[tpenfield]

...and put the controls at WOT. I think there's a sticky somewhere...

I usually forget to do that, get lousy compression results and want to do them all over again :facepalm:

 

[lilboatsman]

...and put the controls at WOT. I think there's a sticky somewhere...

Thanks! I will look for that sticky