Trimming causes miss

[drvred]

I have a 87 Glasstream 172 with a Merc 140. Last year after a long idling trip, it developed a bad miss. I could pull the battery cables lose and reattach them to the battery and it would get better for a couple of minutes and then reoccur. Got home and found the main wire had come loose from the alternator. <br /> Fixed it and ran great.<br /> This year, same problem. I have checked all electrical connections, cleaned battery terms and put star washers under wires. <br /> Checked battery after getting home today, 12.6 volts, running 14.4.<br /> Both times happened after long periods of no wake zones, then started to cut out when I worked the trim up or down.<br /> thank you<br /> Rick

 

[drvred]

Re: Trimming causes miss

Can anyone help?

 

[Bondo]

Re: Trimming causes miss

The Electrical Greamilins are Hard to Chase accross the internet Rick,.......<br /><br />It Sounds like you've been trying the Right Things,......Shake, Wiggle,+ Pull Tests are about the Only Thing that Works.......<br /><br />Make Sure of the Ground Path of the circuits, as well as the Positive side,......<br /><br />I'm not saying that You Did,.. But Grounds are Often Over Looked.........<br /><br />Good Luck,.......

 

[drvred]

Re: Trimming causes miss

Does everything ground to the battery? I checked everything back to the battery. <br /> What are the symptoms of vapor lock? Since long idling or no wake zones seem to trigger it.<br /> Rick

 

[jeff13601]

Re: Trimming causes miss

A lot of boats will " load up " after a long period of trolling. Some people go to a hotter plug to try and alleviate this problem. But this wouldnt have anything to do with loose wires

 

[Aquadzac Captain]

Re: Trimming causes miss

jeff13601 are you saying that low cruise on a large boat could "load up" the motor and when you go to gun it you would stall or sputter rough? How does that happen???

 

[jeff13601]

Re: Trimming causes miss

I have fished with guides who fouled plugs from trolling for 8 hours. And yes, fouled plugs will make a boat sputter. One of the other more exp people here could answer why better, but I would think that running rich in the carb, to cold of plug or leaky rings would be a couple things that would cause it

 

[tommays]

Re: Trimming causes miss

a trim pump at least a new one can draw over 100 amps when it winds up<br /><br />so it does not take to many small problems like bad cables or connections for it cause a problem<br /><br /><br />tommays

 

[DHPMARINE]

Re: Trimming causes miss

A few things need clarifing here:<br /><br />when you saw 14 volts charging in the system,what rpm was the engine running ?<br /><br />when in these no wake zones,and low speed operation how long is long ?<br /><br />has the battery been load tested ?<br /><br />If your battery voltage is low,and if you have breaker point ignition,drawing more voltage from the battery will cause the motor to 'flounder' for sure.Such as using the trim motor.<br /><br />Have you checked the battery ground wire where it bolts to the back of the engine ? Dissconnect the coil wire + lead from the ignition and crank the engine for a minute.Feel all wires and connctions.Any warm/hot ones need cleaning.<br /><br />DHP

 

[drvred]

Re: Trimming causes miss

The 14.5 volts was at idle. <br /> Removed and cleaned all grounds. <br /> Sanded points again and boat ran great with engine covers opened, once closed it started acting up within 1/4 mile.<br /> Rick

 

[jeff13601]

Re: Trimming causes miss

If it is running bad does it always straighten up after you open the engine cover?

 

[drvred]

Re: Trimming causes miss

Took the boat out today after cleaning the main electrical plug on the back of the motor, and installing a new tune up kit. <br /> Boat ran like a champ for 5 hours. <br /> Only question is:With the problem it would fire as soon as you hit the key, now it has to turn over for 5-10 secs before starting. <br /> I am not complaining too much though.<br /> Rick

 

[Don S]

Re: Trimming causes miss

Then it's time to go back over your tuneup and make sure everything is right. Dwell, timing, carb adjustment.<br />Obviously something is still amiss.

 

[jeff13601]

Re: Trimming causes miss

Do you pump the throttle three or four times before you try to start it when it is cold?