[scott324]

I have a 89' 70 HP Evinrude. The tach works, but instead of zeroing out when off it goes to the 5000 mark. Then when running it moves up accordingly until pegged. I did some research here and tried the connecting grey wire from tach to yellow/grey from stator bypassing the rectifier which did nothing. Although I am not 100% sure the test was preformed properly. I was looking at the wiring diagram from my manual and my rectifier has an extra wire(purple) going the to terminal strip. The purple is connected to the grey wire coming from the tach. There was another grey wire connected to the terminal strip that had a jumper to the yellow/grey. I assumed this was not the intended grey wire for the test. This is where I am unsure about the test.On a side note, which may have nothing to do with the problem above, I am having a stalling problems. After running the motor for a little while the engine stalls when I get near idle. If I stay near idle it will eventually die, if I give throttle it does fine. The carbs were rebuilt, but this didn't fix the problem. I idle around 1100 rpms, and have 100psi on all three cylinders. I was told by the local shop this should be ok. I have been told it might be a fuel problem, what else could it be. Just general areas to look at for now. Thanks for any help.Scott

[TxShorty]

Ignition key off or on?Key off, does the tach jump to 5k, or just relax and drift there? If it jumps, then you have some eroneous voltages somewhere, and probobly shoud go and see a mechanic before you continue running!1100 rpm idle is too high too. Tends to break or at least prematurely wear the clutch dog and gears.16 years old... How many running hours?

[scott324]

When off the tach reads ~6k. When started it jumps back to 5k.The throttle screw is back all the way so reducing it can only be time via timing. This is how its been since I have owned it. I assume they did this because of the age????? The hour meter reads 2500. I don't know how accurate it is.I should add that it is the VRO model.

[MCM]

Scott, The idle can be set by readjusting the slow speed idle set screws on the carbs.As for the tach, is this a newly installed tach or has it performed properly and this just started?Here are some instructions for setting the idle in the carbs, your manual will also cover this if you have one. (Carburetor Adjustment - Single S/S Adjustable Needle Valve)(J. Reeves)Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.Note: As a final double check setting of the slow speed valve(s), if the engine has more than one carburetor, do not attempt to gradually adjust all of the valves/carburetors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburetor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.--------------------Hope this helps

[scott324]

MCM,My carbs have fixed Jets, there is no adjustment as far as I know.The tach has been working fine up until a month or so ago. it is original as far as I know.

[MCM]

Scott,Parts catalog shows 2 different carbs for that yr. & hp. one with an adjustable jet & one w/out???As for the test you performed earlier? According to the same catalog you should have a three wire retifier not 4 wire. Maybe you should post your model# so we can figure out what motor you have.

[scott324]

MCM,That will have to wait till I get home this evening. That is where my confusion was, the wiring diagram for my motor only showed 3 as well. I will let you guys no. ThanksAny idea on the stalling problem. This is the most frustrating as it makes it very difficult to get into the ramp. Thanks so muchScott

[MCM]

Not till we figure out what motor it is

[scott324]

Model Number is EVOTLCCASerial Number is G1802589Let me know if you need anything else and thank you.

[MCM]

Hi Scott, the second & third letters should be numbers (horsepower), the CC would indicate a 1988 motor

[MCM]

Scott, even a 1988 70hp. should still only have a 3 wire rectifier. There should be an aluminum freeze plug on top of the motor, check there for the model#, maybe someone replaced the powerhead??

[MCM]

Well Scott,I did some cross referencing using p/n's for 4 wire rectifiers and bottom line is there's not a 70hp motor made in any year by OMC or Johnson/Evinrude that used a 4 wire rectifier, so if you have a 70hp with that rectifier???

[scott324]

Mike, I really appreciate all the help. Here is a pic of the rectifier with wires and the dataplate from the top of the PH. Let me know if you need more information.

[scott324]

To further explain my test while looking at the pic:I took the grey wire attached to the terminal strip with the purple and attached it to the yellow/grey ( which is the 2nd down). Nothing....There is another grey wire attached to 3rd position down, but is jumpered to the yellow/grey mentioned above.Mike, it looks as if the previous owner may have replaced the PH. THe original numbers I gave you were from underneath the outer housing near the Tilt/trim piston on a small dataplate. It was acutally located on the mounting bracket to the transom.Thanks

[MCM]

Well Scott, as near as I can tell someone has installed the wrong rectifier on your motor.Your motor is a 1988 70hp EvinrudeThe correct rectifier should be OMC p/n 0582399 which has been superceded to BMC p/n 0583408. this could explain some of your problems, altough I'm not sure what effect or damage the wrong rectifier would cause.You need to install the proper rectifier, you'll also need to use the wiring diagram to make sure all the wires are connected in the proper positions on the that termial strip.Hope this helps

[MCM]

Oh I almost forgot, is this motor new to you or have you had it awhile?

[MCM]

Scott that is the original power head, same #'s, you probaly misread the 7 as a V

[scott324]

Mike,Thanks for the reply and all the help. Correct me if I am wrong, but the rectifier would have nothing to do with the stalling would it? I have had the boat about 2 yrs. The Stator was replaced about 1.25 years ago. Would the rectifier be replaced at the same time? If I had to guess I would say I have had the stalling problem since the stator replacement, but can't be certain.What would a new stator cost and is there any risk of damage using this one? ThanksScott

[MCM]

I'm afraid it would, you see the 4 wire rectifier you currently have is for a 4-5 amp alternor/charging system. The correct rectifier is for a 6-10 amp sytem which is what your motor is.A faulty rectifier will damage the stator which supplies ac voltage to the power pack. the incorrect rectifier may cause a similar problem. It needs to be replaced and then troubleshoot the system from there.

[scott324]

So are you saying you think the stator may be damaged or a faulty rectifier causes the stator to work improperly? The stator replacement was a costly one here in Tampa.Sorry, the last part I meant what would a new rectifier cost? Any online store you recommend?Thanks a million

[MCM]

Ebay, they also sell them here at Iboats, Sierra p/n 18-5708, or you could try ishopmarine.com $40.99 for an OEM, Sierra is probably as good as the OEM as far as the rectifier goes. As far as your stator is concerned visually inspect it for any cracks or a sicky syrrupy substance dripping off of it. It may not be damaged, there are some tests that can be done with digital volt/ohm meter. replace the rectifier first though.

[MCM]

Scott, this is the correct Sierra rectifier for your motor, click here, it was used on many different hp. & yrs.Do not buy the one they have listed as p/n 18-5827, it is not the correct replacement for your motor.

[scott324]

Mike,Thanks for all the help. I ordered the Sierra rectifier. I looked at the stator and saw nothing visibly wrong. What kind of voltage should the stator be returning at full throttle and Idle? I was reading above 14volts yesterday, but it didn't seem consistant. ThanksScott

[MCM]

Scott,I would be hesitant to run the motor at all until you have the proper rectifier on it. As for the stator, an ohm test can be done without the motor running or the key on.Its actually the rectifier that returns the voltage to the battery, if this is where you're getting your reading.At the stator you should be reading a minimum of 150 volts AC I beleive and 450 - 600 OHMS, I don't have the test procedure for your motor handy at the moment. Maybe Joe Reeves or someone else will come along with the info. I'll see if I can find it in the meantime.

[MCM]

Scott, With the motor off, key off. disconnect the two yellow stator leads from the terminal block, you should get a reading of 450-600 ohms. The fact that you can still run the motor, and no visual cracks or other indications of the stator overheating indicates that the stator is probably still OK.Try to resist the urge to run the motor until you've replaced the rectifier and verified all terminals are properly connected at the terminal block.