70hp all new igniton still bogs! quick help

[RaScLeS]

Re: 70hp all new igniton still bogs! quick help

I know its still kicking on two it revs slow and the number 2 plug is soaked in gas lower carb still wet and the plug isnt even as hot. switched plugs no change. its been 3 summers now and maybe a tank of gas. I have two good switchboxes one oem one aftermarket they both start the engine and run it the same.

I will check the harness but pretty much after a new motor, imagine I wasted alll that time n money and its the harness? oh boy. other then that maybe my new stator or trigger is cooked from running on 2 and messing with it with different coils packs etc....

if thats the case im beat i will check the specs again, pull the harness plug and have a look. really not worth my time but a little more knowlege might be worth my time but barely

thanks again. so the wiring outside of the harness is all new to the choke to everything pretty much in hopes of power. new connectors from my tool box its been gone over many many times to ensure its all done properly.

oh also I checked the rectifier with your procedure and couldnt get continuity on those two stator wires just the positive terminal. so something there is also a problem

 

[RaScLeS]

Re: 70hp all new igniton still bogs! quick help

the harness plug is off, thius plug has the original wires coming out which are all cut and new wires after that. I cannot get inside the plug, so I figure I have to replace this entire harness unless someone gets me inside there

 

[PHE]

Re: 70hp all new igniton still bogs! quick help

I'm certainly no expert on outboard motors. Just trying to help with the things I've learned.

If the rectifier doesn't ring out the way I described, it probably has the two diodes between ground and the stator terminals blown. A full bridge from Radio Shack with a high enough current rating will work for only a few dollars. I'm sure it is cheaper than Merc's.

If the 2nd cylinder isn't firing, it has to be the trigger, switchbox, coil, coil wire, or plug. I would assume that it isn't the stator if the other two are firing. If I remember correctly, the stator powers the switchbox. I have an oscilloscope which made checking the trigger output and switchbox output to the coils much easier. Before doing anything, I would see if you have spark on the plugs. Remove them, put the plug wires on them, wrap some wire around the threads and ground the wires. Then crank the motor and see if you get any fire on them.

If number two isn't firing, first check the continuity of the plug wire. Then swap plugs to see if you have a bad one. Then swap the coil with another cylinder and see if the problem moves. If it does you have a bad coil. Then swap the trigger inputs to the switchbox between cylinder 1 and 2. (Remember to put them back, this is just for testing) If the problem moves you have a bad tigger. If it doesn't and cylinder 2 spark plug isn't firing, the problem is the switchbox. If the new box is blown, you have to find out what blew it.

This brings us back to the harness. Disconnect all the wires that go to everything from the plug and check if any are shorted together with a DVM.

As I said, I'm no expert, so any experts out there, please feel free to correct this test method.

 

[RaScLeS]

Re: 70hp all new igniton still bogs! quick help

going to do the trigger test tomorrow sounds safe enough, the box cant be blown its ran the motor for like 1 minute running time since out of the package. the coils been swapped I have 7 coils, tried different coil wires everything.

"This brings us back to the harness. Disconnect all the wires that etc " From the harness there are all brand new wires...... its inside the harness plug adaptor that may have issues.

this boat has started ran flawless past 5 grand as is and was mint, I shut it off and never got power back. I dont think ill ever understand but keep at it for now THX

 

[CharlieB]

Re: 70hp all new igniton still bogs! quick help

A wiring hanress problem feeding ANY voltage to the switchbox on the black w/yellow trace kill wire can damage that switchbox in a heartbeat.

Disconnect that kill wire at the switchbox, attach a volt meter to the wire harness side and begin testing, watch the meter while a helper turns the key on/off repeatedly and hitting the choke. If EVER you see the meter even flicker, find out why and correct it.

DVA the trigger ouputs to the switchbox, disconnect the throttle cable, and pull the lanyard to kill the ignition.

Test each trigger output cranking the motor while you slowly move the throttle/timing lever from idle to WOT and back. Any variation or dead spot may be a sign of a broken wire where they flex.

 

[RaScLeS]

Re: 70hp all new igniton still bogs! quick help

there are absolutly no broken wires on this engine other than inthe harness clip. I am going to trouble shoot very soon.

There is an opportunity to give into the devil some more there is a working powerhead made by marinier with the same components not sure of the year or if they work for 200 all it needs is a lower unit. thinking about that for now going to try and get the center piston to fire

 

[RaScLeS]

Re: 70hp all new igniton still bogs! quick help

well I did a spark test and as expecting nothing on #2. thanks to the site ive tested this by putting the trigger wire from #1 on #2 and got spark. this indicated the coil and everything work and narrows it down to a fried trigger with numbers in spec??????

again I have 2 packs that wont even run the motor. how they got that way I dont know, another used one that works just as the brand new one. and the new one I just put on a couple days ago.

help???? Might have to just keep this money pit till its fixed and I can stop thinking about it

 

[PHE]

Re: 70hp all new igniton still bogs! quick help

So you didn't have spark on #2 then you swapped #1 and #2 trigger wires going into the switchbox and then got spark on #2 and didn't get any on #1. This would indicate that the trigger or the wires going to the trigger are bad. This also indicates that the switchboxs are good since they fire when given a good trigger signal. Time to pull the flywheel.

 

[RaScLeS]

Re: 70hp all new igniton still bogs! quick help

^ right on. you know what tho I will check to see that #2 trigger on the number 1 piston has no spark to be guarenteed.

very sad case I paid 180$ for that trigger and barely used it. maybe pull the oem trigger off the parts motor $200 or buy another used or new trigger.

that pack is working atleast

 

[ajgraz]

Re: 70hp all new igniton still bogs! quick help

Was your new trigger CDI, brand new aftermarket (e.g., Sierra), or new old stock Merc (as in, possibly manufactured 30+ years ago)?

I bought a new old stock trigger from the late 70's, still sealed in the box. Discovered that the wires were badly corroded way deep up inside the rubber "sleeve" due to the crappy corrosive insulation formulation used back then. Replaced wires and it worked.

 

[RaScLeS]

Re: 70hp all new igniton still bogs! quick help

its a new trigger and appears working, strong spark on all 3 now but no holeshot. the motor runs perfect in neutral revs well. pretty stumped here on how to trouble shoot this now other than the wiring harness itself.

it is not dropping a cylinder I believe its a mixture issue now? what settings are peoples motors at? ive tried it all

 

[CharlieB]

Re: 70hp all new igniton still bogs! quick help

Is the trigger moving freely through its full range of motion?

Disconnect the throttle cable, with the motor OFF, slowly open the throttle and watch the timing advance until you get to max advance, from there on opening the throttle you will 'feel' the additional spring pressure of the timing linkage.

Does the trigger plate rotate until the timing stop contacts?

Too long a stator mounting screw or one in the wrong hole can obstruct the trigger plate and cause low power problems.

 

[RaScLeS]

Re: 70hp all new igniton still bogs! quick help

I have played with the trigger a little bit, I dont know a lot about those parts yet and testing but they are NEW less than 2 hours use, switchbox is new, all coils work, carbs rebuilt etc.

trigger moves freely and stops at full advance like it should, if i push the trigger the opposite way it idles the motor down and would probably stall. did this once to see its affect I dont get how the trigger works.

since spark is all ok I might have my mechanic test it out again theres nothing more I can do other than check inside the harnsses solder joints.

again! one time I went out started my boat and it ran perfect crazy holeshot power and enough power to pass 5000rpm I stopped and re tested the power several times and it stayed. I shut off the motor and that was it no more. if it didnt do that now and then I probably woulda scrapped it.

pics and videos today

 

[RaScLeS]

Re: 70hp all new igniton still bogs! quick help

The video's people!!! seemed like when I put in neutral and rev'd it and put it in gear it had some power to go again but still dies down

Cold start
http://www.youtube.com/watch?v=XimwfiFVa2s
Warmed up and hole shot after
http://www.youtube.com/watch?v=m6Ts7Zr-qhQ

turn it up real loud !!!!

 

[ajgraz]

Re: 70hp all new igniton still bogs! quick help

If it helps, my 1978 70hp is set with the idle A/F screws out 2 full turns from seated (for idle and holeshot), and the idle is set to just a shade under 900rpm (sometimes stalls going into gear otherwise; probably got tired reeds, and I ain't interested in the effort it'd take fixing them).

When you are doing link and synch/timing, do you have the LU submerged in water? Do you have the plugs (except #1) out? Did you first make sure the timing pointer is in the right spot with a dial gauge or digital depth micrometer? I recently very carefully re-did Clams' procedure virtually to the letter, and it's like a different motor now. All our in-common symptoms simply dissapeared.

Still haven't answered Q: is new trigger CDI, new old stock OEM, aftermarket (e.g., Sierra)?

 

[RaScLeS]

Re: 70hp all new igniton still bogs! quick help

I did not order it but is NOT old stock, its brand new aftermarket most likly cdi. I let my mechanic see the video he thinks the fuel pump is not working properly?

anyways funny enough I went in a 50hp 4stroke pontoon boat today and the motor had NO POWER! lmao.....mercurys

 

[PHE]

Re: 70hp all new igniton still bogs! quick help

ajgraz is correct. The idle mixture screws affect much more than idle. They need to be on the very rich side to provide enough fuel to get to high RPM, where the main jets take over. My motor will not get on plane if adjusted for best idle. Mine are 1 3/4 turns out.

Also, as ajgraz mentioned, doing a proper link and sync is critical to getting it running right. This includes setting the pointer using a dial indicator. My pointer was off when I got the motor, so I'm glad I checked it before setting the timing.

Replacing the fuel pump diaphram should be done every year or two. Its a 10 minute job. If they haven't ever been replaced, it would be a good idea to replace the check valves as well. If the checks leak, it will not be able to keep up with fuel. If the diaphram has a hole in it, it will leak fuel into the crankcase and make it overly rich. Either can prevent it from running right.

Since you now have spark on every cylinder, a proper link and sync and fuel pump replacement may solve all the problems.

 

[PHE]

Re: 70hp all new igniton still bogs! quick help

One more thought. I haven't heard you mention that you cleaned the carbs. If you haven't, you certainly should. A dirty carb can lean it out real quick. I had to pull the drain plug and clean the main jet 20 miles from the dock one day to get home. After I got back I gave the carbs another cleaning and I added a fuel filter between the screen and carbs.

 

[ajgraz]

Re: 70hp all new igniton still bogs! quick help

Totally agreed with PHE. The stuff could be 30+ years old, I had to do all that crap with the fuel pump diaphrahm, check valves, inline filter, fuel lines in the cowl, new fuel feed line and bulb, new pickup tube in tank (and carb cleaning of course) to get 'er running right too. Why do we do this hobby again?

 

[RaScLeS]

Re: 70hp all new igniton still bogs! quick help

the carbs were professionally cleaned when I purchased this brick a couple years back. can someone explain how to change the fuel pump screen there are 3 bolts on the fuel pump I guess take those off and the tubes off? we'll see in another week or so