3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

Engine ran great last year when put up for winter. Unable to start enging during spring commissioning. battery fully charged, engine turns over, have spark at plugs and coil, have fuel coming in to carb. The carb was rebuilt 2nd half of last season, and installed new alternator, new points gaped at .022, new distributor cap, new roto, new spark plugs gaped at .035, and new spark plug wires. Friend suggested we check our emergency kill switch, but we can't find one and local DNR tried to find one last year with no luck. Boat is an 88 Sea Ray Seville Bow Rider (20 ft). What is our next step? Only difference between now (when it doesn't run) and last year (when it ran) (other than Minnesota winter) is that we had a mechanic replace the shift cable bellows and transom gasket and O-rings. gas is non-oxygenated with winter additive added.

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

try disconnecting the shift interrupt switch - see if you get spark at the coil

otherwise, click this link:

http://forums.iboats.com/mercruiser...oubleshoot-points-ignition-system-335407.html

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

Puts some points and condenser in it. They tend to glaze over while setting for long periods of time after use. Then they don't make electrical connection, but they sure look good.

This is the cause of no spark 90% of the time on boats that ran fine when put away last winter.

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

Okay, so we have spark, but still not starting...

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

Confirm the accelerator pump in the carb is squirting fuel by looking down the throat of the carb and pump it couple of times. If not, pour couple of table spoons of fuel down the carb and crank. If it fires, move to fuel pump. Unhook line to carb, place container under, crank engine and confirm it is pumping fuel. If all is well, replace plugs. If still no start, look at timing.

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

I have plenty of fuel in the carb. How do I check timing if engine won't run?

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

loosen the distributor, with someone cranking, turn the distributor til the engnie fires - once running check/set the timing

is the firing order correct??

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

Last year did you run the boat after the tuneup?

Timing check/set should have been part of a tuneup after points install and dwell check/set.

You say now it has spark, did you do something in between post#1 and post#4? If so, what was it?

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

Did you put the rotor back in under the distributor cap?

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

To answer why i see spark now and not before - I'm not sure, could be that it was to bright out a the time; although we did read something in the trouble shooting sction of our manual about checking the Techomitor to be sure there are no breaks in the wire - we found it broke and spliced it together. Below are the results of what we have tried and the results so far.

- Mid / end of Last summer the alternator was replaced, the cab was completely rebuilt, and new points, condenser, rotor, and distributer cap were installed (no discoloration on points, rotor, cap).
- at winterization the plugs, and plug wires were changed along with oil. fuel additive was added to a full tank of non-oxygenated fuel.
- we have a full charge on the battery.
- the spark plug gap was set at .035.
- the points were set at .022.
- i pulled the plug wires and checked for spark at a engine ground and have spark for all 4 plugs.
- pulled the coil wired from the distributor and have spark.
- there is good fuel entering the carb.
- Checked continuity at the coil + and - side by removing all wires and that checked out.
- disconnected the neutral safety switch on the top of the engine and tested spark and that passed.
- tried spraying starter fluid in cab, but still didn't start.

don't know where to go from here to get engine started. i do have a new set of points and condenser, but have not installed them yet. it seams as if a safety switch or fuse is not functioning. boat ran at winterization until it died from the fogging agent.

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

Has this boat run since you rebuilt the carb? What do you mean by "plenty of fuel going down the carb" the amount that it takes to start it shouldn't even be visible to the eye (unless you're actuating the throttle). I think you probably have a float that is too high and your needle isn't seating. You're flooded, and that's why you're not getting it started, you have spark and starting fluid won't help. Just a guess.

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

My guess is you have crossed some spark plug wires (probably 3 and 4). If 2 are crossed the engine will not start. I know this from first hand experience .

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

smassey22180 said:

My guess is you have crossed some spark plug wires (probably 3 and 4). If 2 are crossed the engine will not start. I know this from first hand experience .

Click to expand...

Double check the firing order and make sure the wires are on correct.

The timing shouldn't be off from anything you've done. Did you start the boat after doing the plugs and wires or was it already winterized?

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

My bayliner did the exact same thing last year, turned out to the kill switch. I unplugged the two wires going to it and connected them and it started right up.

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

The carb was rebuilt mid last summer so we used it the entire senond half of the season. what i mean by plenty of fuel is when i open the butterfly and look in while an assistant (wife or me) moves the throttle forward to the start position or pumps the throttle once or twice to prime the engine when cold, i can see fuel entering the carb through the jets into the venturie.

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

I don't believe i crossed the wires only because we have inspected them 3 or 4 times thinking the same thing, and we checked rotation and firing order in the manual. Also, these were installed last fall and the boat ran until it stopped during the fogging process. do you think it's possable a plug could have cracked over the winter?

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

We checked rotation and firing order in the manual and on the boat 3-4 times, so i would be surprised if that'as the issue. Plugs and wires were installed last fall, and the boat ran until it stopped during the fogging process. do you think it's possable a plug could have cracked over the winter?

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

I think you would have a lousy running engine with one cylinder out, but it would run.

Have you ever pulled the plugs out after trying to get it started and smell/ check for gas in the cylinder itself? The plug should be wet with gas, and you would most likely flood the engine trying to start it if it is getting gas to the cylinder and not starting.

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

I have not smelled the cylinder, only the plugs - they had a gassy smell. i did not feel the plugs so i will try that on Friday when i am at the boat again. you say the plugs should be wet, and if the if i continue to get spark at the plug it should start. if it's not starting it's follding - corect? if it's flooding and not starting my next question would be what would cause that (other than to much gas in the carb) could it b a stuct needle?

Re: 3.0L 4 cyl. mercruiser, cranks but won't start - no spark?

Yes, if you have been cranking as long as you say, trying to start it. And the carb is full of gas squirting down the throat when it's pumped.. it won't take long to flood the engine with gas then it will be tough to start from being flooded. At that point the plugs should be physically wet with gas on the tip. If the tip is dry... then put some gas in the actual cylinders... (not a lot) screw the plugs back in and see what happens....