OMC Starting problem

[DC698]

Hi all, I have a '91 Sunbird with the OMC Cobra 302 engine. Brought it to an OMC certified mechanic in July for a stalling/idle problem. Engine would stall whenever I returned throttle back to neutral with engine at normal operating temp. Mechanic did full tune up including plugs(which were rusted solid in block), adjusted carb, timing, etc. and also found that the shift module was bad and changed that. Replaced the old shift cable (which was already the "new" red one) with a new one. I did notice that the old one was starting to get hard to shift. Got boat home, tried on lake -- Brought boat back to him because boat was stumbling AND stalling in reverse (RPM's were also high at idle (around 1100)) He fixed idle problem, and adjusted shift cable. When I went to pick up boat he told me it runs great now, shifts with "2 fingers" and goes into reverse no problem. Except NOW, he tells me there is an intermittent starting problem. He tried starting it once and nothing happens...wiggles the wiring harness and it starts no prob. does it to him 2-3 more times, Checks the fuses - fuses fine, he tightens the battery cables and it starts. He tried to duplicate it 3-4 more times but it kept on starting for him. I got it to the lake and sure enough, it wouldnt start. Tried 10 - 11 times wiggling the harness and cleaned the battery cables-tightened and still nothing! Finally, had the key in ON position while wiggling harness and other various wires near engine and volt meter finally pops up to 10V. Try starting engine...nothing!! Shut key off, turn back on and it Starts right up! Boat ran great (As it did before I brought it in for tune up, cable, etc etc) until I had to shut it off at marina. And sure enough, when I went to start it, nothing happened. Wiggled harness and it started. Brought it back to him. Luckily problem happened to him again. Checked the battery and noticed one cell was gone in battery. Replaced battery with new one and had the boat for three days just to try it each day (He didnt want to see the boat anymore...as I didnt want to keep bringing it to him!!) Of course boat started each morning and afternoon for him. Picked up boat last Saturday. He started it for me..started right up and ran as good as before. Got it home, hooked it up to the muffs and turned key..nothing again!! (S.O.B.) Not a happy camper at this time. Turned key off, turned back on, and poof.. started up. HERES the kicker--put my blower switch on while it was running, and it killed the engine ..????? Shut key off, turned off blower -- turned key to ON postion..Battery gauge showing app. 9-10V..hit blower switch and battery gauge pegs to Zero volts and I notice tach indicator arm going in counter clockwise direction (almost redlining in the oppsite direction) Turned key off, turned blower switch off.. noticed it did it with any accessory switch turned on..like the bilge pump. 3-4 more times it finally started again. Somtimes the battery gauge will show voltage and engine still will NOT start. Tried it today and engine started fine and ran fine. Shut it off and started it back up 2-3 times. I did notice when it was running that the dash lights were flickering and when I turned the blower on I could here a slight miss in the engine (like it was putting a load on the engine)Battery gauge shows it is charging (Bouncing between 14-16V with engine revs at approx. 12-1300rpms) Could it be an alternator problem? This is driving me nuts, because now I have to bring it back to him. (Side note: Mechanic has been really good taking the boat back A.S.A.P. --like next day)When the boat IS running, it runs perfect, no knocking, grinding, hesitation, etc etc...<br />Any ideas on what it could be??! Is it a bad ground somewhere?? Sorry post is soooo long. Wanted to include everything I could think of. Thanks for the help.

 

[Boatin Bob]

Re: OMC Starting problem

It does sound like a bad connection somewhere, you've already cleaned the battery connections but take them off again amd make sure corrosion isn't inside the wire under the insulation, also take the black wire off the engine block and clean it, plus the positive wire probably goes to a slave solenoid, clean there as well, your symptoms sound exactly like a bad connection, especially when you turned the blower on, it sucked down your voltage too low to fire the coil, you must have a high resistance build up somewhere.

 

[sea wolf]

Re: OMC Starting problem

have u checked batt. connections to the starter? make sure there's no rust on them & there good & tight. the fact that he had to wiggle the wires to get it started makes it sound sound like a bad connection/ground somewhere. i wouldn't trust that gauge either. have the alternator checked out.

 

[DC698]

Re: OMC Starting problem

Thanks Bob and Seawolf for the quick replies. I am going to check and clean the connections you both told me about right now. Talked with the mechanic this morning about it again. Had doubts about the alternator working properly because I saw the dim, flickering lights on the dash when it WAS running. He told me he had already checked and tested the alternator and that the flickering could be caused by a bad ground or connection somewhere. I also asked him if he had checked the ground wire from block to earth ground, and he said he did and also cleaned the terminals/connections at starter, starter solonoid, etc. Has him and I baffled right now as with any intermittent electrical problem will. He told me to check under the dash for any loose ground connections. He told me that the accessories should have nothing to do with overall starting of the engine..they are on a seperate circuit (Which makes sense, because they work without key in "ON" position.) but it is a mystery why putting the blower switch on killed the engine when it was running!!? Going out now to check under dash and check fuses again. He told me to check the 50A fuses (2 of them) again. He checked them before.. but may be a bad connection there.. Told me to drop boat off (again)if I didnt find anything and it happens again. Thanks again for the replys. And sorry for the long post again!!

 

[Boatin Bob]

Re: OMC Starting problem

Yes...for this problem you have to stop thinking logically, I had a problem once with the 50 amp fuse that feeds the slave solenoid (the other one feeds the tilt/trim motor) inside one end it had biult up some corrosion so that it got hot enough to melt the solder holding the fuse together and it became open, but before it finally opened my guages were dancing all around, I shut off the engine and went to start it again but it wouldn't until I metered the fuse and replaced it. Do you have a manual with the wiring diagram for the engine and dash?

 

[DC698]

Re: OMC Starting problem

Bob, Yes I do have the Clymer manual with the wiring diagrams for the dash and engine. Checked and cleaned the cables yesterday. Same problem still. Tested voltage at the starter assist and it was good. When it was dead, with key on, I tried to wiggle the purple/black wire attached to terminal of starter assist and it got the gauge to show 10V. Could not replicate the problem again, of course by wiggling the wire! Seems like when it does start, and I run it for maybe 1-3 minutes, then shut it off...and then turn key it has nothing.. then I wait 2-3 minutes and turn the key and it has voltage!?! I've been going through the wiring diagram, but still nothing.

 

[Boatin Bob]

Re: OMC Starting problem

When you say 10v, is this on the voltmeter on your dash? Do you have a small multimeter? If not you may want to purchase one. You shouldn't see 10v you should have at least 12 to 12.5 volts if the battery is OK. If you truly have 10v then something is pulling it down and you need to start at the battery by disconnecting cables until you see what is causing this.

 

[DC698]

Re: OMC Starting problem

Bob, Unfortunately, my multimeter grew legs about a year ago and havent replaced it yet. Should get another one soon. When I said it had 10V, that was a reading from the gauge. Today I tried it out again and it started up just fine and ran fine. The first thing I did was take out the two 50A fuses and check them out. The one for the tilt/trim was in good condition..no corrosion at all and metal contacts were clean. Took out the other 50A fuse for the engine and it had much more corrosion on it..the fuse itself inside the glass tube was white and pitted with corrosion. Also had a couple of small tiny brownish spots around glass tube area and near metal contacts..I was able to scrape off with fingernail. Could this cause a intermitent bad connection?? Cleaned up the metal contacts on the fuse and inside the fuse holder. I then swapped the fuses to see if my tilt/trim would act up. Turned the key and it didnt act up at all. Showed 12 - 12.5V at battery (According to guage) and fired right up. Tried it 10 times or so.. and it worked fine. Tried the tilt/trim and that also worked fine. Put the key on and hit blower switch the same as I did yesterday, and it didnt kill the engine..as it was yesterday. The dash lights aren't flickering anymore either when the engine is running. Could it of been the fuses?? I am going to replace the corroded 50A fuse tomorrow. Noticed my ignition switch fuse had the same corrosion (Whiteish all over fuse inside tube) so I replaced that one today also.

 

[andrewgroup]

Re: OMC Starting problem

When you have troubles like this you have to do things that will isolate the trouble....Swapping fuses was a good Idea, along with cleaning them thoroughly...Sounds like you've isolated the trouble and you can revoke the paper certification from he your Mechanic.<br /><br />Something I would have done to help isolate the trouble would be to clamp a jumper cable from the battery post, (if using wing nuts) ir the wing nut post if using posts...from the battery directly to the same bolt on the start that the + lead normally goes to to isolate the cable. I've seen green corrosion throughout the complete length of the cable.... These are really cheap I replace them about every 4 to 5 years...Also spray them with a CRC protective coating...<br /><br />I also use two sewing needles piercing the insulation of the wires about 2 inches from the fuses. This makes a very small hole but you can then put the leads of your digital voltmeter on the needles and if you see a voltage of any significance when you engage the starter or simply turn on the ignition you know you may have a problem...<br /><br />this technique is extremely useful and I keep a small needle packet in my toolbox....<br /><br />I suggest that when things are working good, you take some voltage drop readings across a variety of circuits and record them for future reference.

 

[DC698]

Re: OMC Starting problem

Thanks for the tips, Andrew! The sewing needle tip is a really good idea.. now I have to figure out a way to sneak some out of my wifes sewing kit! (Haha) I havent heard of the CRC spray but it sounds like a really good idea. Is it a silicone based spray coating? Makes sense though being in a moist environment. Hopefully my problem was with the main engine 50A fuse being corroded. Hate to get out on the water and have it happen again! I'm going to invest in another multimeter this week too, so I can get some accurate readings.

 

[andrewgroup]

Re: OMC Starting problem

http://www.crcindustries.com/productinfo.asp?productno=05046 <br /><br />copy this into your browser address line, should be able to get at a local napa or similar parts store....Don't be afraid to spray this onto any exposed connector....<br /><br />Also, know that the majority of condensation and corrossion occurs when the motor isn't running. If you are trailering the boat. Leave you engine cover open immediately after boating for several days if you can. Let this area dry out thouroughly after each outing......

 

[Boatin Bob]

Re: OMC Starting problem

I would still go ahead and replace that 50a fuse and probably get a spare because you just can't get those babies anywhere. Since my problem I've carried a couple just for insurance. If you have a spare you won't need it, if you don't have one...well you know what happens! Anyway it sounds like you are a lot closer to fixing it...good luck!

 

[DC698]

Re: OMC Starting problem

Thanks for the link Andrew. I am definately going to check that out. I do leave the engine compartment open about half way when not in use to keep air flowing through it. I never used to, but noticed moisture forming on top of valve covers and other misc. metal parts. After that, I left it open to air out. (Just bought the boat last october) Got a new polyester/cotton cover this year for it too.. but need to get some vents for that before I put it up for the winter. I noticed it gets pretty warm under the cover when I take it off to take the boat out. Bob, I picked up 4 extra 50A fuses today at the local marina. Definately worth having the extra ones on board!! I also have a bunch of various size ones in the glove compartment. Like you said, if you dont have them on hand..thats when you need them..but when you do have them..you dont need them! Worth the peace of mind. Didnt get a chance to start it today yet. But I hope it was the corroded fuse contacts that was my whole problem. Going to go out later and try it out and then switch the fuses over with the new ones. <br />Thanks again!

 

[JustMrWill]

Re: OMC Starting problem

Hmmmm....<br />I am having same problem. I turn key and just get a slight "click". I hooked up boaster cables and it turned over. Bought a new battery and I am getting the "click" and my up tilt is not working. **** ..was hoping that I wouldn't be re-wiring this year...(already replaced all fuses). Bought this this boat (87 4.3l V6 OMC) because it was too good a deal not to. *Sigh* Thanks all...gotta love when your problem gets answered before you ask it.<br /><br />-JustMrWill<br /> '87 Regal Majestic 210XL Cuddy Cabin<br /> 4.3L OMC Cobra