4.3L V-6 OMC just stopped starting?

jpreiss

Recruit
Joined
Aug 7, 2004
Messages
3
Gents,<br />I've a 1989 Thundercraft with abovesaid motor and it just stopped cranking. Symptoms--when key is turned to start, engine makes a sound like it is trying to turn over (a chunk sound) and then nothing. Engine does not turn after that. First, I tried jumping-no worky. Got a new battery but same result/symptoms. Then I swapped the starter and mounted solenoid but same result/symtoms. Tried screwdriver across solenoid too but same result/symptoms. <br /><br />Boat has run excellent all year and just had it out last weekend for a day of skiing and no problems. Cooling gauge read fine and so did oil pressure. Boat sat in yard covered all week (no rain) but now it will not start. <br /><br />My level of expertise is I used to restore jeeps with mild engine maintenance and I know aircraft engines very well. Not too indepth I can handle. Have a repair manual for the engine also. Any help/ideas/suggestions would be greatly appreciated. Thanks!
 

Elk Chaser

Petty Officer 2nd Class
Joined
Jul 29, 2003
Messages
186
Re: 4.3L V-6 OMC just stopped starting?

You tired the obvious stuff other than, does the engine rotate. <br /><br />So first I would see if you can you crank it by hand.<br /><br />Even with bad wiring the screwdriver trick will turn the engine over every time. Does the solenoid at least engage when jumping the posts?
 

Blk-n-Blu

Master Chief Petty Officer
Joined
May 12, 2004
Messages
821
Re: 4.3L V-6 OMC just stopped starting?

Jp, Pull the spark plugs and try to turn over the motor with the starter, You may be hydrolocked.<br />Look for water in the cylinders when plugs are removed. note: serious engine damage can happen if you try to start with water in the cylinders also Check the oil for an increace in volume on the dip stick.
 

jpreiss

Recruit
Joined
Aug 7, 2004
Messages
3
Re: 4.3L V-6 OMC just stopped starting?

Thanks a bunch for the suggestions and ideas. Tonights troubleshooting:<br /><br />Engine rotates about a clock position. i.e.- a bolt on the front pulley goes from 9 o'clock to about 1030 o'clock and that is as far as it will rotate. This is by starter or by hand (wrench), with and without sparkplugs. Oil is nice color with no milk or metal. Plugs didn't have any water although it sat covered in yard during the week in 100 degree wx. Friggin hot down here south of Hotlanta. Plugs smelled nice and gasy.<br /><br />Hooked a wire from the S connector on the starter solenoid directly to the battery. Same result/symptom. Voltmeter says 12.5 at the battery and at the starter solenoid with ignition key in run. Can't check in start as I'm divorced and would try and have her tongue test it. lol<br /><br />There's an assist solenoid in the schematic. Any thought that this is the culprit. Or maybe wire shorted to ground between assist solenoid and starter solenoid is draining power. But, then again, I could only manually turn the pulley the same distance as the starter was.<br /><br />About to call in the repairman. Thought I could at least find the core problem. Anymore thoughts?<br />Thanks again for the help thus far.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,308
Re: 4.3L V-6 OMC just stopped starting?

Pull the Outdrive..........<br />Make Sure it's the Engine that's Locked Up..........<br /><br />You Don't have a Wiring Problem.........<br />You Seem to have a Very Serious Mechanical Problem...........
 

Elk Chaser

Petty Officer 2nd Class
Joined
Jul 29, 2003
Messages
186
Re: 4.3L V-6 OMC just stopped starting?

Yup, that motor should very easily turn all the way around by hand with no plugs installed. If it is stopping at all or even a change in resistance you have a mechanical problem.<br /><br />Like bondo said you can disconnet (pull) the drive to make sure you don't have a problem with the drive. <br /><br />After that, if the engine still will not turn around easily then it is time to pull the engine and see what's up.
 

jpreiss

Recruit
Joined
Aug 7, 2004
Messages
3
Re: 4.3L V-6 OMC just stopped starting?

Thanks for all the help, ideas, and suggestions. I am at this point maxed out on talent and am calling in the big dogs (certified repairman). <br /><br />Hoped I could avoid it, but don't want to really have to pay.<br /><br />Thanks again all, <br />May your water be glass,<br />and your carves sharp.<br />Chicks dig the slolam.<br />Joe
 
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