Not much spark

[Blk-n-Blu]

Re: Not much spark

Jimmy, I would be looking for a new electronic ignition / distributor I bought one two seasons ago and "no more points or weights /springs" and no more problems.I got the Prestolite distributor,cap,rotor wires and coil for about $130.00 New

 

[sculbert]

Re: Not much spark

That would have nothing to do with your timming light and weak spark. Are you sure you are getting a weak spark? We are talking about two different things here. It is easy to use a timming light that has a spark advance adjustment on it that allows you to run up the rpms and find out what the total advance is on your distributor. That is the only way to test timming advance. I don't have a shop manual for your engine to tell you the total advance and what it should be. find that out and get your self a timming light with the advance knob on it. You just run the rpms up and turn the kjnob to find out the total advance of the engine spark. You might find that the timming light was your problem if that is your problem.

 

[hoot]

Re: Not much spark

i think i saw a post a while back where someone had a similar problem. they finally took the boat to a mechanic and found that the alternator was the problem. you should check voltage at the battery with no engine running and then with engine running. and report volts at your coil.

 

[jimmmy]

Re: Not much spark

From what I've read, the 3.0L had a Delco distributor and points. I'm reasonable sure that when I replaced the points last year, the Merc dealer sold me Prestolite points. Could this be part of my problem?

 

[achris]

Re: Not much spark

Only one number for points on this engine listed in the merc manual. -34235.<br /><br />If the points fitted in without the use of a hammer , then it's a good bet that they're the right ones. Did you check the dwell angle with a dwell meter? Points set at the wrong gap can cause weak spark.<br /><br />$0.02<br /><br />Chris..............

 

[Boatist]

Re: Not much spark

First at WOT what is your speed at 3000 rpms??? Could it just be your tach is set for the wrong type engine. Set to a 6 cylinder instead of 4 cylinder.<br /><br />I like to do a compression check and make sure that is good to start with. Have you checked compression and if so what are your readings???<br /><br />I would hook up a dwell meter and make sure it is 31 to 34 degrees or .018 gap. Leave the dwell meter hooked up when you make your run and see if it changes at high rpms. If it changes then I think you may have the points installed wrong. You may have points spring hook up where do not have enough pressure to close the points and at high rpms they will float and the dwell will change. Make sure the plate your points mount on has a ground wire attached and it is not borken. I am assumeing you changed the condenser at the same time you changed points.<br /><br />If you think you are loosing spark try gaping plugs to .030 or even .025. This will stop spark from blowing out from low voltage. <br /><br />Change your high tension wire from the coil to top of distributor to a solid wire not carbon. This wire is most likely to fail first as it fires for every cylinder not every 4th cylinder like the spark plug wires. Also it will affect every cylinder not just one where you would notice a miss. If your problem is low voltage this solid wire should help some. Are your spark plug wire Factory wires or some type of cheap carbon wires. Some spark plug wires have higher resistenance per foot than others. Note many new cars have a much higher voltage than than a 1988 boat would have and the wire sets they use also likely to have higher restenance. So some inductive timing light may be designed for this higher voltage and not work well with a standard 1988 ingition.<br /><br />I have to disagee with those that say minus side of the coil should read 7 volts with the points open. With the points open it should read battery voltage or 12.6 volts on both sides of the coil. With the points open you will have no current flow and with no current flow it will read battery voltage. Running should have about 8 to 9 volts on the plus side of the coil. I hoping when you changed the coil you put the standard coil on it.<br /><br />If it is not a spark problem then it could be valves need adjusting. They should be set to zero lash plus 3/4 to 1 turn down. If they do not open enough then at high rpms you will not get enough fuel and air in cylinder.<br /><br />Carburetor, are the jets for both barrels getting fuel??? Does you carb have a power valve that is plugged up??<br /><br /><br />I hope this will give you some new ideas and help you get on the right track.<br />Good Luck.

 

[flashback]

Re: Not much spark

one other thing, you mentioned smelling fuel in the oil, most common cause of this is a bad fuel pump and if you do have gas in the oil it will ruin the engine. I understand you can have a sample of your oil analyzed at a lab, someone here may know a web address for this...or you could just put a new pump on, change the oil and filter, and you should be good..

 

[jimmmy]

Re: Not much spark

Checked voltage at the coil when running.....get 10.5 on the + terminal and 7.8 on the - terminal. Does it sound like my alternator is bad??