ignition issues

[1966starcraft18ft]

Hello all. I have a 1966 starcraft holiday 18 ft with a mercruiser 110 i/o. Last weekend, we took the boat out and it ran great. no issues. Put new bilge pump in the ol girl on tuesday and gave it a crank to start it up and nothing. cranked but no fire. So i started diagnosing and found that i have appropriate voltage at coil, points are working. i replaced the plugs, wires, cap and rotor. I still am not getting spark at the spark plugs. coil was replaced a month ago with an internal resisted coil. I have spark coming out of the coil at the coil wire.

I need some help figuring this out. I am at the point that i am starting to think the coil is the problem. I did finally find out that this motor needs an eternally resisted coil instead of an internally resisted.

 

[Bt Doctur]

If you have spark from the coil tower then the points are still working, check to see if there is spark coming from the dist cap wires. If not, the rotor may be cracked, grounding out the spark from the dist cap.
Internally resisted simply means the resistor is built in to the coil ,
"use external resistor" means you need a external resistor or resistance wire to drop the voltage.
using a non resistor coil with a resistor or resistance wire drops the voltage way too much.

 

[gm280]

Seems if you already verified that you do have a good spark out of the coil, but not at the plugs, then you already zeroed in to the problem area. Now figure out where that spark is going (or not going as it seems) and fix that issue and happy boating... :thumb:

 

[1966starcraft18ft]

See, that's the thing. I have replaced the rotor because that's where everything is pointing towards but no fix. So, then i started thinking that with 1,000's of volts, there was a resistance problem so i replaced the wires, plugs,cap & points. still nothing. i even replaced the wire from points to coil & still nothing. So, i am turning towards you guys for help i that i might have missed something.

 

[Bt Doctur]

the lobes are opening and closing so you have spark at the coil tower. are you testing to the coil tower or using the towers lead to a good ground?the coils lead could be bad
To not have spark at the plug wires could mean the rotor itself is not turning or grounding out the spark.

 

[Bondo]

coil was replaced a month ago with an internal resisted coil. I have spark coming out of the coil at the coil wire.

Ayuh,.... Ya already know ya got the wrong coil,.....

The Spark comes outa the coil, through the coil wire into the center of the cap, to the rotor, to whichever lead to whichever cylinder, to the spark plug wire to the spark plug, to ground,....

You've got a break in that sequence, somewhere,.....

 

[1966starcraft18ft]

ok. so after a week of racking my brain and visitng with you all and buddies of mine. I have concluded that the new internally resisted coil is in fact the culprit. this coil is to test 3.25 ohms across the primary but mine tests 1.2 ohms so i will be turning it in for warranty(per my part guys instructions).

Bit of good news, for my birthday, my beautiful other half ordered me a new radio and speakers for the boat. should be here tomorrow. It's a pyle plcd6mrkt.

 

[1966starcraft18ft]

for those of you who are gonna say, i cant use an internally resisted coil, i have full battery voltage at the coil with no resistor.

 

[1966starcraft18ft]

ok, so here's an update. i have spent a little time away from the boat with other stuff. I came back to it last night and was working on it. i pulled coil wire and cranked it over again. have a spark but didn't seem very big so, then i pulled cap off and bridged the points with a screw driver and same response. i then started touching the screw driver from the points spring to the breaker plate and i had a huge beautiful spark. so then i set points down on the base circle of the points lobe and then moved the points arm with same screwdriver do point were being operated manually by me and little to no spark. then i inspected the points again and the arm has gotten hot. It's all blue and red.

So, i am picking up another set of points tonight after work and installing them. cross fingers they are the problem.

 

[Bondo]

then i inspected the points again and the arm has gotten hot. It's all blue and red.

Ayuh,..... Too much Voltage is burnin' 'em up,.....

 

[1966starcraft18ft]

So, I have to apologize for somthing,
A while ago i made a smartass comment about the coil i had put on and it being internally resisted. I sincerely apologize. was out of line and I was wrong for thinking that the internally resisted coil would be ok.
With that being said, I have an update.
I put my new points in last night and still wouldn't start, so then i started thinking outside the box and i walked over to my 1964 ford f100 and borrowed its coil, hooked it up, and wouldn't ya know, it fired right up like it had been running for an hour. So, i will be going to my local mercruiser dealer and ordering the correct coil & ballast resistor.

When i got this boat, it never had a ballast on it so i just went on the assumption that it was an internally resisted coil due to there being 12 volts at the coil. until recently, i never knew different til i came across the manuals on boatsinfo.org.