2003 125 ELPTO - Flaky Tach and poor high speed running when warm

Fitchin

Recruit
Joined
Aug 30, 2005
Messages
4
Hello all, Just found this site recently and haven't found anyone with the same problem I have, so here goes.<br /><br />Tach problem. Works just fine for the first little while (say 10 minutes). Once engine slightly warmed up, tach goes completly dead. Stop to do fishing for a while (engine cools), tach works again on startup, but then craps out again soon after. I've already checked gray wire out of the rectifier to tach and as far as I can tell all is intact (no pun intended).<br /><br />High speed operation problem. You probably already know this is a 2+2 engine. When cold, engine runs beautifully through entire power band. The other 2 kick in around 2000 RPM (I'm guessing at the RPM here). I can run 3/4 or full throttle as long as I want and still continues to run great even when warm (hot). Problem is that when I run at about 1500-1800 RPM for about 20-30 minutes, and then give it more throttle (to get the other 2 cyls to kick in) I get major shake, vibration engine hesitation and the other 2 never kick in. If I back down the throttle, to below 2000 RPM engine runs great. Stop to fish for 1/2 hr or so (engine cools) on start up things run great again. Just seems to have this problem when engine has been run under load for a while. Took it to the dealer and he ran it at high speed idle for 1/2 to get it warmed up but couldn't re-create the problem. I've done some reading here, but want to see your thoughts. I have some thought of my own, but don't want to sway your ideas. <br />Are the tach problem and the poor high speed operation problem related? <br />Solutions?<br />Thanks in advance for your advice.<br /><br />Craig
 

jaxsun

Petty Officer 3rd Class
Joined
Aug 9, 2004
Messages
84
Re: 2003 125 ELPTO - Flaky Tach and poor high speed running when warm

craig i have not an answer for you but a question about your motor...do you get really poor performance before the secondary carbs kick in or is the motor strong all the way through?...mine feels like its struggling to plane out until i reach 1800 rpms and the secondary carbs kick in...real aggravating...it also dies trying to load it on the trailer...sorry i cant help you with your problem and im not really tryin to hijack your thread im just curious
 

Fitchin

Recruit
Joined
Aug 30, 2005
Messages
4
Re: 2003 125 ELPTO - Flaky Tach and poor high speed running when warm

My motor is strong all the way through with very good performance before the secondary carbs kick in. Hope you are surviving in Loiusiana.
 

dakk1

Chief Petty Officer
Joined
Apr 22, 2003
Messages
418
Re: 2003 125 ELPTO - Flaky Tach and poor high speed running when warm

Could be stator or rectifier failing.<br /><br />Dave..
 

Fitchin

Recruit
Joined
Aug 30, 2005
Messages
4
Re: 2003 125 ELPTO - Flaky Tach and poor high speed running when warm

Would one failing cause the other to fail?
 

dakk1

Chief Petty Officer
Joined
Apr 22, 2003
Messages
418
Re: 2003 125 ELPTO - Flaky Tach and poor high speed running when warm

I think if a rectifier/regulator was overheating it could damage the stator.<br /><br />Dave..
 

Fitchin

Recruit
Joined
Aug 30, 2005
Messages
4
Re: 2003 125 ELPTO - Flaky Tach and poor high speed running when warm

Thanks Dave, I just want to make sure I replace the right one first. Don't want to replace the Stator if the rectifier is damaged and have the rectifier damage a new stator. Is there an easy way to check the rectifier. From what I've read, testing the stator is somewhat complicated.<br />How confident are you on "could" damage the stator?
 

dakk1

Chief Petty Officer
Joined
Apr 22, 2003
Messages
418
Re: 2003 125 ELPTO - Flaky Tach and poor high speed running when warm

Check the rectifier with an Ohms test.<br /><br />Compliments of Chris1956:<br /><br />Lubedude and others, If the rectifier in question is the standard three post model, then the test is to use an analog ohmmeter across diode pairs. Specifically, that rectifier has four connections including the case, which is ground (-12VDC), since the motor is negative ground. Set the ohn meter to RX1 scale and put one meter lead on the +12V post, the other on one of the two AC (stator) posts. Now switch the leads. You should have no continuity one way, and when you switch the leads, you should have continuity. Repeat the test for the other AC post and +12V post. Now try the same test using the case ground to each of the AC posts. If all the tests show continuity one way, and none the other way, the rectifier is good. If a pair of connections show no continuity either way or show continuity both ways the rectifier is bad. <br /><br /><br />You can also Ohms test the stator but not always conclusive. Can ohms test OK and still be bad. You need a DVA(direct voltage adapter) to accurately test stator performance. Cost about $40 and use with a multimeter.<br /><br />I wouldn't assume anything at this point without further testing.<br /><br />Dave..
 

dakk1

Chief Petty Officer
Joined
Apr 22, 2003
Messages
418
Re: 2003 125 ELPTO - Flaky Tach and poor high speed running when warm

Of course you could just disconnect the rectifier and see if your problem persists. I hesitate to mention this although I have done it many times with no ill effects. There are some that believe you risk damaging the switchboxes. So...<br /><br />Dave..
 
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