PLEASE HELP- All ignition experts please see this thread!!!

[veritek_dragger]

I have a 1983 Mercury V150 on my bass boat and it is constantly fouling plugs. A local mechanic told me it could the the regulator rectifier. That is definitely bad because the tach was erratic and now not working at all. Im under the impression though that the reg/rec only controls current to accessories, battery charging and tach? I don't see how it has anything to do with the ignition system. Could it be shorting out and causing the stator to overheat maybe- this makes the most logical sense.

I question the mercury switch because I notice when I trim the motor down is when it starts sputtering and running really rough. If I trim it level, it runs 4 times better. Any thoughts are appreciated. Thanks in advance!

 

[Maxz695]

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

the mercury switch kills the engine when it,s tilted up. thats it,s function. I had my tach going nuts on me yesterday in the fake lake. also my volt gage showed little to no charge I rewired alot of gorunds on the dash and still not much helped at that point while charging the battery (Only getting a click to start it) I saw one of the terminals (top to side post ) The screw was coming undone from it I changed the battery terminal and everything today worked as normal. Who would have thought it was that simple. as far as fouling plugs if this is a two stroke the gas may not be mixed well enough or too much oil with the gass. 50:1 ratio is recommended but even that seems a bit much in my engine as well thats 8 onces per 6 gal. I use about 7 now but I would rather by new plugs than to have to buy a new engine be careful and mix your fuel well!

 

[narvlebenoit]

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Max I mix 16 oz. to 6 gallons in my 25 jonhonson and my 90 mercury and I dont foul any plugs.

 

[Maxz695]

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

thats definitely not a 50:1 ratio

 

[veritek_dragger]

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

I thought that it could possibly be the oil mix (or lack thereof). I go 50:1 with Quicksilver and premix the oil in 1.5 gallons of gas in a can, then dump it into the tank before adding the remaining amount. Im wondering if that is not enough. Its just odd that the motor bogs and cuts out when trimmed down at idle. On plane I have no issues. Im suspecting a weak spark but does anyone think it could have anything to do with the rectifier/regulator? I definitely know that is toast, as sometimes wide open it will only show12 volts, other times 14, sometimes 16. Plus the tach only works intermittently. I doubt its the trigger because I hear those either work or don't- no in between. Stator is suspect, but it is only 2 years old. The big suspect on my radar is that mercury tilt switch though- if it is designed to cut out the motor and is bad, it could be part of the problem (again only suspecting because depending on angle of motor, it idles good and bad). I guess Im curious though if when tilted forward does it complete the circuit to cut out, or disengage the circuit to kill the motor. Im wanting to bypass it to rule it out as a suspect.

 

[Faztbullet]

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Could it be shorting out and causing the stator to overheat maybe- this makes the most logical sense.

Yes!!! Fix the rectifier before stator is damaged.

I question the mercury switch because I notice when I trim the motor down is when it starts sputtering and running really rough. If I trim it level, it runs 4 times better

Tilt switch will not cause this problem, thing that will are:
1) rectifier/stator problem
2) flooding carb/s
3) exhaust ports buried under water at full trim in
4) recirculation (bleed) valves plugged/dirty/bad
5) timing off or bad idle stablizer

 

[Maxz695]

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

and disconnect the tilt switch for the time being

 

[j_martin]

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Ignore Max, he can't even count. (8 oz in 6 gallon is 96:1)

Rectifier shorted can stress the stator, and if the ignition is marginal, cause it to misfire. Disconnect and tape up the two yellow wires going to the rectifier (on starboard side, switchbox mounting plate) for now. If it runs well, that's your problem. If you don't address it, you will eventually take out the stator.

Otherwise, the best route would be to check out and tune up the engine in a systematic manner. Compression first. Then verify the stator and switchboxes with the DVA tests. Then decarbon. then carb kits and adjustment, and if you bought the problem verify model and jet sizes and location. Then fuel pump kit. Check the condition and routing of the bleed hoses, and verify correct operation of the bleed check valves. Then a timing and linkage adjustment procedure should put it in top shape. This list covers all of Faztbullet's concerns and a little more.

If the floats are set a bit high, and you tuck the engine in past level (motor) they'll likely flood. Even if they're in good shape they don't really like that position because of high fuel level and high back pressure on the exhaust. Carb kits are probably the most needed part of the above list.

hope it helps
John

 

[veritek_dragger]

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Thank you all for the much needed info. You have all confirmed my suspicions and contributed much needed info. I am going to disconnect the mercury switch and the rectifier to confirm if this is the issue. A short in the rectifier makes sense in that it can eventually lead to a 'too hot' stator and cause malfunction. I am also going to disconnect the idle stabilizer as well, as it sounds like this has caused the same issue for other people and please correct me if I am wrong, but it is not required for operation?

I am brand new to the forum and must say this is such a wonderful resource, but it would be nothing with out you guys so thanks again and I will let you guys know the end result!

 

[veritek_dragger]

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Ignore Max, he can't even count. (8 oz in 6 gallon is 96:1)

Rectifier shorted can stress the stator, and if the ignition is marginal, cause it to misfire. Disconnect and tape up the two yellow wires going to the rectifier (on starboard side, switchbox mounting plate) for now. If it runs well, that's your problem. If you don't address it, you will eventually take out the stator.

Otherwise, the best route would be to check out and tune up the engine in a systematic manner. Compression first. Then verify the stator and switchboxes with the DVA tests. Then decarbon. then carb kits and adjustment, and if you bought the problem verify model and jet sizes and location. Then fuel pump kit. Check the condition and routing of the bleed hoses, and verify correct operation of the bleed check valves. Then a timing and linkage adjustment procedure should put it in top shape. This list covers all of Faztbullet's concerns and a little more.

If the floats are set a bit high, and you tuck the engine in past level (motor) they'll likely flood. Even if they're in good shape they don't really like that position because of high fuel level and high back pressure on the exhaust. Carb kits are probably the most needed part of the above list.

hope it helps
John

John here is a quick rundown of the situation. Bought the boat 5 months ago and been battling this issue ever since. Did fine on the test drive, but the first time out I didnt realize the kill switch was engaged and I drained the batter cranking it over. I used a jumper box to start it, and that day is when the problem started. Im assuming I shouldnt be jump starting the boat? Since then, Ive gone through a ton of spark plugs, rebuilt all three carburetors and the fuel pump. Changed the impeller and thermostats (one wasnt opening). Changed all of the fuel lines and new bulb. and ran a can of seafoam through the fuel system.

Im excited to dig in to the electrical suggestion you all have made. I have a question in regards to the decarbonizing- what would be your recommendation on the best and most efficient way to do this without having to run a whole tank of gas with sea foam?

Thanks again...

 

[Maxz695]

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Ok so it,s not the first time you,ve been wrong either J so according to your caculation 6X8 = 48 X2 making 96 % so if i put 6 gallons and just over 4 onces this would be 50% 6X4 24 X2 48 % ? I was going by the recommondations on the oil bottle for onces to gallons.

 

[j_martin]

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Ok so it,s not the first time you,ve been wrong either J so according to your caculation 6X8 = 48 X2 making 96 % so if i put 6 gallons and just over 4 onces this would be 50% 6X4 24 X2 48 % ? I was going by the recommondations on the oil bottle for onces to gallons.

:facepalm:

1 gallon = 128 oz.
6 gallon = 768 oz.
768 / 8 = 96

That's 96 parts gas to 1 part of oil.

Now go away.

 

[j_martin]

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

John here is a quick rundown of the situation. Bought the boat 5 months ago and been battling this issue ever since. Did fine on the test drive, but the first time out I didnt realize the kill switch was engaged and I drained the batter cranking it over. I used a jumper box to start it, and that day is when the problem started. Im assuming I shouldnt be jump starting the boat? Since then, Ive gone through a ton of spark plugs, rebuilt all three carburetors and the fuel pump. Changed the impeller and thermostats (one wasnt opening). Changed all of the fuel lines and new bulb. and ran a can of seafoam through the fuel system.

Im excited to dig in to the electrical suggestion you all have made. I have a question in regards to the decarbonizing- what would be your recommendation on the best and most efficient way to do this without having to run a whole tank of gas with sea foam?

Thanks again...

The rectifier on that thing is real cheezy. Just draining the battery and expecting it to recharge it probably got the rectifier in about 10 minutes. I usually replace them with one of these.

It's a bridge rectifier. Find it surplus, or new for under $4.00 Needs to be 20A or better, 200V or better ratings. Never replace it again.

There's a FAQ on decarbon on this site. Basically use a pony tank, mix up seafom and about a gallon of well oiled fuel so thick it's ridiculous. Run it through the engine till it about dies. Let it sit for an hour or 2, or overnight, then run it on 2 cycle fuel. Change the now thoroughly fuddled up plugs, and yer good to go.

hope it helps
John

 

[veritek_dragger]

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

This bridge rectified sounds good and well priced how is it wired though? Are there any diagrams on this site to assist?

 

[j_martin]

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

This bridge rectified sounds good and well priced how is it wired though? Are there any diagrams on this site to assist?

Four terminals labled ~ ~ + - . Yellows go to the ~ connectors. Tach wire goes to either. Red goes to +, and - goes to frame ground.

It gives off a little heat, though less than the original. Drill and thread a hole in the switchbox mounting plate so you can bolt it firmly to the plate. that should do it for the heat.

I soldered wire loops to mine so I could use the original terminals and machine screws.

hope it helps
John

 

[veritek_dragger]

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

This helps tremendously! Thanks John!

 

[veritek_dragger]

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

Re: PLEASE HELP- what is the function of the Mercury tilt switch on Ignition System?

UPDATE- after many hours of troubleshooting and help from member J_martin and others I finally fixed the problem. It turned out that the port bank switchbox and the low speed stator were bad. Only 360 dollars in parts and and about 1 hour of personal install time and boom, the problem is fixed! The motor purrs like brand new. I hope this thread helps anyone else experiencing the same issues.

Tight lines.....