1989 3.0L Mercruiser wont start..

[jamOner]

I have a 1989 3.0l Mercruiser (4cylinder inline) and I cannot get it to start any longer. It started fine about 3wks ago (first time of the summer), ran cool (under 150degrees), and all was well. Since then the only thing I have done to the boat is remove the blower (still out - but think this is unrelated). Today I tried to start the boat again and it cranks and tries to start, just wont turn over. Has gas, good battery, and not sure what else. Any ideas what to check?
Thanks in advance!
Dustin

 

[mhunt]

Re: 1989 3.0L Mercruiser wont start..

sounds to me like it maybe an ignition problem. Check the ignition system (distributor cap, rotor, plugs, wires). Pull the cap off the distributor and see if there is and condensation or build up on any of the contacts.

 

[Don S]

Re: 1989 3.0L Mercruiser wont start..

Do you have spark?
When was the last time it had a full tuneup?
Do you have a points distributor?

 

[jamOner]

Re: 1989 3.0L Mercruiser wont start..

sounds to me like it maybe an ignition problem. Check the ignition system (distributor cap, rotor, plugs, wires). Pull the cap off the distributor and see if there is and condensation or build up on any of the contacts.

Other than checking for condensation, how do I check these systems?

Do you have spark?
When was the last time it had a full tuneup?
Do you have a points distributor?

I am pretty sure it is sparking, the engine is turning really well just wont fire to a start - sounds like it is going to start then stops. I am not sure about a full tuneup, but I had the spark plugs replaced 2 summers ago and it was only used about 10 times since then (also replaced battery, impellar, water pump, gimble bearing, bellows, ect). Also, not sure what a points distributer is?

also, thanks for the quick responses!

 

[Don S]

Re: 1989 3.0L Mercruiser wont start..

I am pretty sure it is sparking,

Not good enough. The engine cranking over fast enough has nothing to do with having spark or not.
To check for spark, pull the coil wire out of the distributor cap and hold the wire 1/2" from a clean ground and have someone crank the engine over. It should jump a bright blue spark.
Check it, don't assume it has it.

I am not sure about a full tuneup, but I had the spark plugs replaced 2 summers ago and it was only used about 10 times since then Also, not sure what a points distributer is?

What you need is a service manual, and a full tuneup.

 

[mhunt]

Re: 1989 3.0L Mercruiser wont start..

after you check to see if your coil is working, go from there. the next place the 'spark' will go will be through the distibutor rotor and to each of the four contacts inside the distributor cap. For the electricity to flow it needs clean, shiny metal to conduct the spark. If the rotor or contacts are worn or have a build up of greenish corrosion then it will not flow electricity. If this is the case, either go ahead and buy a new cap/rotor/plugs/wires or shine the contacts up with some sand paper but becareful not to take off too much material as you do not want too much gap.

 

[Robj]

Re: 1989 3.0L Mercruiser wont start..

I don't even check points, rotor, cap. If you do not know the last time you had a tune-up, well you should just be changing them. Cleaning points is a waste of time, if they are that bad they should be replaced. Change the ignition wear parts, rotor, cap, points and condensor and then start troubleshooting.

Have a great day,

Rob.

 

[Maclin]

Re: 1989 3.0L Mercruiser wont start..

I would double check that no other wiring was disturbed inadvertently when you removed the blower.

It (blower motor circuit) could also have been providing some sort of ground (I have seen stranger things), or the prevous owner(s) may have tapped off the blower motor for something else. I'm just sayin.....

 

[labguy3232]

Re: 1989 3.0L Mercruiser wont start..

Do what Robj just said: replace the plugs, wires, cap, rotor, and points. Be sure to SET THE POINTS CORRECTLY. I had the exact same problem on the same set up and would not start. Put new points in and DID NOT set the points correctly and nothing changed. I finally set the gap correctly and boom! Fired right up and ran great. If you need help setting the new points, reply back. I think the gap is .016-.024 if I remember correctly.