Changed Plug wires and distro cap - now boat will not start

[halcrimm]

Good evening all,

Mercruiser 3.0L Alpha 1 Gen 2 I/O.
S/N OD714746 Engine
S/N OD671270 Transom
S/N OD665768 Drive

Have had the restored boat in the water twice over the last week and it ran fine except when I would go no wake speed and right by dock and the engine would die. Managed to restart each time. Runs great faster than 5 knots through WOT. Had an engine mechanic take a look and he suggested I replace the plug wires and distribution cap. After replacing cap and plug wires the engine ran very smooth on the muffs. Better than it ever sounded. That was yesterday. Today I took the boat to drop off at marina to have some trailer work done. Put the boat in the water and tried to start to move to correct pier and the engine would not start. All I get is the whrrrr of the starter. Engine never tries to turn over. I did pull each plug wire and reseat to make sure nothing was loose.
I will say that the set of plug wires that I got from my Mercruiser dealer down the road is a a little short on one wire. The pack came with two long (plug 3 and 4), two medium (plug 1 and 2), and one short for coil to distro cap. The coil plug was about an 8th of an inch to short because of having to wrap aroind the wires to the Delco EST style cap. So, I swapped the short wire with the medium one that was going to plug one and put the medium length wire on the coil to the cap. Does this make a difference?

Sill learning.
Hal

 

[dswi]

Re: Changed Plug wires and distro cap - now boat will not start

I believe that they are interchangeable...but maybe not.
Do you still have the old wires? Try putting the 1/8" short one (old) back on and see what happens.
Did you pull the wire by the boot? Could have pulled the end connection off???

Try the old wire for the short one and make sure the coil wire in on the coil and distributor cap, not a plug.
Hope this helps.

 

[DAN M VAGOS]

Re: Changed Plug wires and distro cap - now boat will not start

Are you saying the starter is turning but not turning over the engine because it sounds like the starter is not engaging thats what it sounds like your saying.

 

[DAN M VAGOS]

Re: Changed Plug wires and distro cap - now boat will not start

And if the starter is just spining and not hitting the engine then you need a starter and if what you are saying is the engine IS turning but wont start the plug wires have nothing to do with it seeing how you had it running the day befor.

 

[dswi]

Re: Changed Plug wires and distro cap - now boat will not start

The starter can be taken apart and cleaned up if it is not working...might not have to get a new one...if that is the problem. I did it to mine and it was easy...Need a 9/16 socket to get to the 2 bolts that hold it to the engine (if my memory serve me correctly. Sometimes they get corrosion in/on them (being in a wet/humid environment)...

 

[halcrimm]

Re: Changed Plug wires and distro cap - now boat will not start

Maybe I didn't explain quite right. First the starter is new. Installed a few months ago. Never a good idea to try and do sound effects in writing. Starter is fine. Engine tries to turn over but will not catch and run. Can hold the key in run for a few seconds but never starts just tries. Was also doing some reading wondering if old lower shift cable could be issue with stalling when going no wake speed or neutral.

 

[Eric 3.7LX Alpha 1]

Re: Changed Plug wires and distro cap - now boat will not start

Is the rotor installed? Believe it or not... it's happened a few times....

 

[halcrimm]

Re: Changed Plug wires and distro cap - now boat will not start

Rotor is installed. I started it yesterday after all work was done while on muffs and it started fine and ran smooth. I let it run up to steady 140 degrees then after a few more minutes I turned it all off.

 

[dswi]

Re: Changed Plug wires and distro cap - now boat will not start

How far is it to the marina?
Could something have jiggled loose (plug, connector, etc...) during the drive to the marina?
(if the roads are 1/2 as bad as SC roads, this could be a cause for the run/no-run situation)

 

[dswi]

Re: Changed Plug wires and distro cap - now boat will not start

Was also doing some reading wondering if old lower shift cable could be issue with stalling when going no wake speed or neutral.

When you set the idle speed, did you do it in the water tied up (tightly) to the dock or in the yard??
I don't know if this matters but it might change your actual idle speed with the engine "loaded" vs "unloaded"

 

[NHGuy]

Re: Changed Plug wires and distro cap - now boat will not start

Did you bump the kill switch/lanyard? Wouldn't b the first!

 

[halcrimm]

Re: Changed Plug wires and distro cap - now boat will not start

Okay, so now here is my question. Came home and put on the muffs. Before I ran the engine I did change the spark plug wires around. By that I mean, I swapped the ends from plug to distro cap. Now all plugs have rounded end on plugs and flat ends in distro cap. Tried to start engine and it started right away and sounded great. Could the direction of the plug wires really cause me not to be able to start?

 

[Eric 3.7LX Alpha 1]

Re: Changed Plug wires and distro cap - now boat will not start

If the distributor cap has "male" pointed ends like the spark plugs do.... then I would think the wires could be swapped backwards without issue. Both ends of the wires would have the same type of boot.

If the distributor has female ends for the wires Then you aren't going to get a connection.

 

[bonzoscott]

Re: Changed Plug wires and distro cap - now boat will not start

When your problem occurs, check for spark. An inline spark tester about $5, is easiest. I have the feeling since the stater was replaced, you have an intermittent connection. Clean all wire connections at starter and may even add star washers on the solenoid wires (if not already there). Clean connections at coil. Clean both end of battery cables, battery terminals - and if battery is using wing nuts use pliers to tighten well.

 

[RichRab]

Re: Changed Plug wires and distro cap - now boat will not start

Sounds like the wires were reversed. You should feel boot going on and off of connection. You can ground a spark plug at motor end and see if it sparking. Good luck.

 

[alldodge]

Re: Changed Plug wires and distro cap - now boat will not start

Had an engine mechanic take a look and he suggested I replace the plug wires and distribution cap. "I'll guess he changed the rotor, points and condensor as well" After replacing cap and plug wires the engine ran very smooth on the muffs.
tried to start to move to correct pier and the engine would not start. All I get is the whrrrr of the starter. Engine never tries to turn over.

Maybe I didn't explain quite right. First the starter is new. Installed a few months ago. Never a good idea to try and do sound effects in writing. Starter is fine. Engine tries to turn over but will not catch and run. Can hold the key in run for a few seconds but never starts just tries. Was also doing some reading wondering if old lower shift cable could be issue with stalling when going no wake speed or neutral.

Wording is different but I take it every time the engine cranks but will not start. May or may not have spark because that has not been checked yet. If it doesn't have spark, check the points and see if the mechanic forgot to tighten down the points sufficiently.

 

[tank1949]

Re: Changed Plug wires and distro cap - now boat will not start

More than once!!!!!!

 

[alldodge]

Re: Changed Plug wires and distro cap - now boat will not start

Have you checked for spark yet, either with a spark tester or holding the coil wire near a ground?

 

[halcrimm]

Re: Changed Plug wires and distro cap - now boat will not start

DSWI, I haven't set idle speed and actually didn't know I needed to. I will look in the stickies to see if there is a procedure there. Any guidance would be appreciated.

We did check for spark when at the pier the day the problem occurred and my buddy said that he saw nothing. I did not recheck when I got the boat back home. I just reversed the plug wires from plug to distribution cap and tried to restart. At that point engine ran fine again. Is there anything obvious that I am missing that would allow an engine to run on the. Jeff's just fine but not allow the engine to start sitting pierside?

 

[dswi]

Re: Changed Plug wires and distro cap - now boat will not start

I have heard of some that will set the idle speed in the water tied up to the dock (tightly) and some that will set the idle speed in the yard on muffs.
For mine, the FACTORY SERVICE MANUAL says 650-700 rpm in open water (with someone else steering). The FSM will give you pictures and all.
If the idle speed is too high it could cause drive problems later in life...
I believe the FSM also says that the timing should be set at idle speed...if idle speed is wrong, timing will/might be wrong. = bad running engine. make sure to set dwell (with a dwell meter)(if you have points) before you set timing. Point gap will change timing, but timing will not change point gap.