merc 260 won't crank

[DamnitBadger]

78 Mercruiser 260 (350) with a mallory point distributor. No spark. Coil windings check good, about 10.5 volts on the + leg of the coil, neg. connections to distributor are good, point gap set correctly @.016. I cleaned the points and checked all connections. What am I missing? Ran fine last week. Fired right up!

 

[Bt Doctur]

Re: merc 260 won't crank

safety switch at the helm,shift interlock switch not centered. grounded neg. wire to/at/in the dist.

 

[Silvertip]

Re: merc 260 won't crank

It isn't the kill switch or he would not have 10.5 volts at the coil. With the aid of a helper measure the coil voltage with the key in the start position (engine cranking). 10.5 volts is what you should see with the engine running (ballast resistor in the circuit). When cranking, you should read near battery voltage (12 - 12.6 volts). If not, the ballast resistor bypass contacts in the solenoid are not working or the circuit between the solenoid and ballast resistor is open. Are you sure you set the point gap at the high point of the cam lobe? Condenser could also be bad.

 

[trog100]

Re: merc 260 won't crank

"wont crank" means wont turn over on the starter motor to me.. but then again i do live in a different country..<br /><br />trog100

 

[DamnitBadger]

Re: merc 260 won't crank

Well I got it to start. I took the coil neg. wires off and left only the dist. wire connected and then had spark. Reassembles with all wires and still had spark. Started and let it run for a while to recharge the bats, after about20 minutes of idle I tried to shift into forward (rpm 900) and it dies. Itried to restart and no spark again. The problem seems to be in the helm control. Gently rocking it back and forth while starting and it will fire.<br /><br />Now for a new problem! It dies when ever shifted into reverse or forward. I ran the idle up to 1100 and no dice. I think the starter is weak because when warm it does not want to do it's job with the robustness that it should. Any thoughts on the shift problem. This is all taking place in my driveway and the water is begining to accumulate in large puddles! LOL

 

[Don S]

Re: merc 260 won't crank

For one thing, you need to explain what you mean when you say "No Spark" do you mean there is no spark going to the spark plugs or the starter won't turn over. With your description, it's hard to tell.<br />If you get the starter to turning by moving the shifter, that is a neutral safety switch problem, but has nothing to do with the ignitions (spark to the spark plugs) side of the system.<br /><br />Next is your idle, don't shift it at 1100 or even 900 or you won't have a drive clutch for long.<br />You have a shift cable problem. Corroded, bad, worn out or something causing it to be stiff and holding the shift interrupt switch to the on position which kills the ignition side to allow the shifter to come out of gear when under load.<br /><br />Get a manual and read it before you destroy things.<br /> Online Service Manual

 

[DamnitBadger]

Re: merc 260 won't crank

No spark from the coil so no spark to the plugs.It cranks (starter turns motor over)fine when cold but when warm the starter is laboring.<br /><br />On to the shifting problem. the cutout switch is not centering properly(thanks Don). The lower shift cable seems stiff when disconnected and operated by hand. This may account for the cutout switch not centering and disabling the ignition. As this unit has an old style shift cable are they still available or do I need to tap the unit to accept the new style? If that the case I may just take it for service.<br /><br />A little back ground on this boat it's a 78 model Cobalt with a 260 mercruiser. the boat was damaged in Ivan last year in a rack collapse. Boat fell 20+ feet and landed in its bow but believe it or not there was no stuctural damage, only cosmetic to the railing, paint and the interior catapulted forward. She stood perched on her nose for two weeks before being lifted and set upright. I purchased her at an auction and reinstalled the interior fixed a couple of small gouges and replaced the railing. It looks great, I just need to work out these minor bugs and it will make a great boat.

 

[Don S]

Re: merc 260 won't crank

With no spark to the coil, I'd say the first thing you need to do is a complete tuneup. Points, condenser, cap, rotor, and sparkplugs.<br />The points are probably glazed over causing the intermittent spark.<br />Worn or dry starter bushings could cause the starter to drag. You might also check that you aren't getting a little water in the cylinders, that could really slow down the cranking, or even hydrolock the engine if enough water gets there. Bad riser gaskets or bad manifolds or risers could cause the problem.<br />Since you just got the boat, I would start from scratch and do all the maintenance checks on the engine and drive, all oil changes, pull the drive and inspect the ujoints and gimbal bearing, new impeller, along with new fuel filters (check for water in the old filter).<br />The old shift cables are NLA (No Longer Available) you need to tap out the bellhousing for the new style cable. All that info on the drive is in the link I gave you earlier for the outdrive service manual.<br />Good luck with your new money pit.....I mean boat

 

[DamnitBadger]

Re: merc 260 won't crank

Is it nessesary to pull the motor to tap the thru hole for the new style cable?

 

[Don S]

Re: merc 260 won't crank

Click on the link below for info on changing the shift cable on your Alpha drive. It has nothing to do with the engine bellhousing, it's the bellhousing the drive attaches too that has to be retapped. All the info is also in the link to the service manual I gave you before.<br /><br /> Shift cable replacement