70hp all new igniton still bogs! quick help

[ajgraz]

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

Years? If there's been a period of more than a month or two where it hasn't been run, it needs another carb cleaning. IMO on these beasts it's a yearly (at least) maintenance item. Not hard at all for the DIYer.

Fuel pump: yeah, essentially you just undo the three bolts, replace the two gaskets, one rubber diaphragm, and two check valves (held in by a small bracket) and yer good to go. Take a good look at how everythings in place, all those parts have to go in a specific way/direction/orientation and any one of them can be mis-installed.

Most kits only have the diaphragm and gaskets, you want Quicksilver 76575A9 (or 21-13424A1) kit because that has the check valves, too.

 

[PHE]

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

I usually pull the drain plug on the carbs if I know I'm not going to have it out for a few weeks. Gets the dirt out of the bottom of the bowl and stops the gas and oil from turning to varnish. Adding a not too fine (50 micron?) filter between the fuel pump and the carbs also helps, but for some reason I find myself lucky if I don't have to clean the carbs once a year.

 

[CharlieB]

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

Intermittant spark on a cyl needs to be checked out, find theproblem and deal with it.

Most lilkely culprit is a broken trigger wire, currently working, it is going to fail again.

Spark test or DVA test the trigger wor the suspect cyl with the motor OFF and the throttle cable disconnected. Move the timing throughout its range of motion while testing. verify that it fails.

If the trigger is a recent purchase contact the seller and address the problem, otherwise decide if you want to re-wire the trigger.

 

[RaScLeS]

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

I can do some tests when I get time I found a coil to not be working and thru it out now anytime I check there is spark.

When I stored the boat I ran the motor out of gas and fogged it.

After reading clean carbs again redo fuel and all that I'm pretty tired of this brick but hopefully get it going some how

Thanks for help!

 

[trhinehart32]

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

i need a switch box do u no where the cheapes place tto get one for a 84 mercury 70 hp 3 cylinder

 

[RaScLeS]

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

ebay 107$ as said in the thread.

to add to this long never ending story I am going to get the fuel pump and check valve done with new lines and what not.....maybe get a plastic fuel tank. i feel im just wasting my time and money though got better things to spend on

 

[RaScLeS]

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

the old johnson i had never once had the carbs cleaned, simply store the engine and use it next season. it was only 25hp but id be out on the water for sure! Fuk

 

[RaScLeS]

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

decided to play with the black anchor today and was very impressed with the power out of the water (of coarse) but more so this time and running prime!! I launch the boat.

boats starts and runs good, warmed it up for only a minute since I ran it earlier about half an hour in the bucket.

put it in gear and it hauled A-s-s till it bogged out and died and would not get me to shore ! after pumping the ball it would run in neutral all day long but not in gear now.
I did not just punch it i eased it to half and had plenty of power to impress me and cruise
but then it died!!!!!

I just cleaned and replaced the seals in the fuel pump and replaced the fuel lines. mhmmmmm

once again failure, carbs are flooding or losing fuel or not being supplied fuel in gear I suppose. help?

all im going to do today is re adjust hte idle mixture screws according to the merc manual

 

[ajgraz]

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

Have you not yet disassembled and cleaned the carbs (and replaced the needle-and-seats) since the rebuild a few years ago that you mentioned?
You can replace anything and everything else but you won't run right w/o clean carbs.

 

[PHE]

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

Sounds like a clogged main jet or a bad fuel pump. I'd take the carbs off, clean them, especially the idle circuit and main jet. Replace the needle and set the float correctly. Then replace the fuel pump diaphram and check valves. I'd also add a fuel filter between the pump and the carbs, but I think I mentioned that before. These parts are not very expensive and typical service that you need to do at least every couple years.

 

[RaScLeS]

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

I wasnt too interested in doing that work and some how it just takes off now and then...

I last adjust the idle mixture with it in gear at the dock as low as the rpm goes (around 700)till it goes lean and dies. then back 1,1/4 turn out I believe.

I try this later on today then back out it comes if I can even get it to the ramp! see about these carbs.

I did take the supply line off the motor after the fuel filter and cranked it to see a good fuel flow. lots of fuel comes out.

 

[CharlieB]

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

I wasnt too interested in doing that work and some how it just takes off now and then...

Sorry, but you have a serious problem with NOT following sound troubleshooting advise.

You have already proven an intermittantly failing spark on #2, yet you refuse to properly test to find out why, your motor will continue to have intermittant problems until you test it, prove the problem fault, and make only the necessary repairs.

You have already replaced most of the ignition system needlessly. Do it right for once and be done.

After the ignition is finally repaired, then you need to follow the directions to adjust the idle mixture correctly. Idle mixture MUST BE adjusted to best idle while IN THE WATER and IN Forward gear, PLUS almost another 1/8 turn out (CCW) to provide the additional fuel for crisp acceleration.

When to are ready to really fix your motor, follow the advise already given, then repost your success.

 

[dlplost]

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

Verify you firing order. Merc made 2 versions of the 3cyl 70hp. one uses 1,2,3 order the other uses 1,3,2.

 

[RaScLeS]

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

the firing order on this one is 1-2-3. I am pulling the carb tomorrow the spark problem is fixed the coil was thrown out and spark is always on all 3.

I believe the carb to be the issue parts will be on order maybe I can get a run.

edit I have someone familiar with these engines coming by hopefully to show me what to do with the carbs and check it over. he thinks it could be the reed valves "the engine can't draw enough vacuum to suck the required fuel through the carbs"

 

[PHE]

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

Reed valves only come into effect at or near idle. If it idles fine, the reeds are fine. Above ~1500 RPM they are wide open.

 

[RaScLeS]

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

^ i remember reading that somewhere now come to think, she can idle very low.

I had the carbs off today and not too bad of a job! there was dirt particles in both float bowls I cleaned it out with tb cleaner premix and compressed air. I did not have time to soak them but if no luck I will. I did not make any adjustments everything looked to be seated like it should be and is all very clean (cant believe I paid someone to do this once)

also new fuel lines all throughout this motor now. only old part here is the gas tank and the motor internals themself

wish me luck again

 

[PHE]

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

The fact that you had dirt particles in the bowl indicates that the carbs are probably part of your problem. Simply cleaning the bowl doesn't clean out the jets and ports. You need to pull the main jet out and clean it out with spray cleaner, then blast the cleaner through all the ports, especially the idle circuit. Back the idle screw out some, then spray through the circuit and reset the screw. Then you need remove the float and clean the float needle and port. Replacing the float needle is also not a bad idea. Finally, you need to set the float to the proper spec.

Also, a clean carb becomes a dirty carb in 5 minutes if the rest of the fuel system isn't clean. Did you also clean the fuel filter screen? Add a fuel filter between the fuel pump and carbs?

 

[RaScLeS]

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

AHAH! this motor is back in service!!! out for half an hour doing w/e the hell I want floor it cruise at 4k supprised I put it back properly. I adjust the idle mixture to 1-3/4 turns out via mercury manual. hole shot is fair once it picks up.

NOW, the top carb is leaking fuel at idle. how do I fix this? and the idle isnt as great as it could be. ( I just tried this 10 mins ago so havent done anything else) also the plunger for the electric choke solenoid fell out as I was removing the airbox I figured out what it was when i tried to use the elec choke. any pictures how that goes back in ? lol I used manual choke cause i was to eiger.

THANK YOU ALL! if you are reading this and your 70bogs rebuild and clean the carbs

phe I am taking your advice, I will get a filter asap and put it on the line. also with my fuel coming out the carb issue im sure these carbs will be off again and gone over again and do it fully. finally the black anchor does something

making a new video and show some close up of what the motor is looking like

 

[PHE]

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

Fuel coming out of the carb is probably due to the float/needle not closing right. Perhaps dirt, needs a new needle, or isn't adjusted right. Remember to put the filter between the fuel pump and the carbs, not before the fuel pump. Don't get too fine of a filter. 25-50 micron is best since the pump is very low pressure and a real fine filter will restrict flow. Finally, when you take the carbs off, check if there is a filter screen on the inlet to the carbs. If there is, remove it since they tend to cause problems due to the small size. The new added filter will work much better.

Sounds like you are almost there. Good luck and have fun.

 

[RaScLeS]

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

thanks, if its still leaking I will tear it apart and replace the needles and floats, I got a filter and am going to check what micron it is if it shows me. there is no screens in the carbs.

I was going to ask about the filter I had it in my hand and was like hmmm fuel pump supply line or carb supply line? so carb supply line it is, and great!!! it sure could use a proper filter there. motor never missed a beat and could go anywhere it seems right now.....but its a 79' and im still affraid to go far lol the 4.3 inboard is my reliability

edit: the package just says universal 1/4" fuel filter. I will look at the filter it self later and maybe it will say on its casing. dont want any restriction it barely hits 5k as it is but I need to adjust the trim