Crazy Idea...1974 Mercury 1500 Manual Fuel Sprayer for cold starting

[Zac Penn]

My tower of power, like everyone else's I have been told, is VERY hard to start when it is cold. I always have to turn it over for ever before it tries to fire. However if you use starting fluid it will fire right up. I do not have the original controls on my motor so i don't have the high idle lever, and slightly pushing the throttle forward doesn't seem to help much. I know for a fact that the choke is working as I can watch the two paddles drop over the carbs. I have completely torn down and cleaned out the carbs, and flushed the fuel system/lines clean. I installed a water/fuel separator that filters down to 10 microns I think so nothing has gotten in there to clog them up again. Priming bulb is nice and hard when I try to start it, but nothing really works except starting fluid.

My ideas is to rig up some kind of spritzer into each carb opening that is tied into the fuel lines. Then run a squeeze ball or something up to the controls so I can spray the premixed fuel into the carbs without taking off the cowlings. Anyone ever try something like this? If so can you help save me some time and report what worked for you?

 

[Chinewalker]

Why not add a fuel primer/enrichener like that found in the later model motors? Much simpler and safer than something rigged together with duct tape and twisty ties. You'd need to machine a hole into the flange of each carb to plumb it, but it could be done.

 

[ondarvr]

Low compression can cause hard starting, but on to you're question.

Much easier would be to use existing outboard parts and mount a primer valve, it just feeds fuel directly into the intake for cold starts.
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looks like CW beat me to it.

 

[Zac Penn]

The motor has between 145 and 151 PSI on all six cylinders so that isn't an issue. Thanks for the suggestion. I will look into that primer/enricher/valve

 

[emckelvy]

You are definitely going to ruin your engine's innards by using starting fluid, unless it's the type that contains oil along with the ether. At any rate, still not a recommended practice, since the stuff is highly explosive and if you have a spark leak, BOOM!

Great Minds Think Alike, because the idea of adapting a priming system already has been done by quite a few folks, including my good buddy, Dr. Frankenmerc!

Just mount the primer valve used in late-model ADI Merc's (look up an '87 115, for example), plumb it up, and you'll be back to instant starts!

To power the primer, when you remove the old choke solenoid, route that wire to the primer, it'll work when you push the choke button (or hold in the key, depending on your style of control box). Note that for this to work, you need to pump the bulb up hard (you should already be used to this!), and keep the primer activated while the engine is cranking, until it starts.

I've posted a pic from the Doc which explains his way of doing the mod. Instead of drawing from the carb bowl, you could always splice a reducer tee into the main fuel line, and run the smaller line over to the primer as the fuel feed. His way of doing it is very creative and replcates the original way Merc did it (in the carb bowl).

Note that the primer discharge side is plumbed into a tee which is spliced into the balance tube assy that runs along the Stbd side of the crankcase. I'm thinking you should put that tee in the upper hose, to allow gravity to feed priming fuel to the rest of the cylinders. Piece of cake!

HTH............ed

 

[emckelvy]

Here's a few used primers of different styles on eBay, take your pick, any should do the job but some might be easier to mount:

http://www.ebay.com/itm/321744295456 Off a 90hp 3-cyl.

http://www.ebay.com/itm/261826823927

http://www.ebay.com/itm/390224589376

HTH...........ed

 

[racerone]

OMC has used a primer / injector since 1980.------I have installed that unit on an inline 6 Mercury .------No more starting problems.

 

[Fed]

Could be easier to find a second hand controller with a fast idle lever and set it all up as intended by the mfg.
Choke plates must be completely closed when energized.
Maybe also review your starting technique?

 

[racerone]

Most controls have a fast idle feature.---Perhaps ask a shop to show you how it operates.

 

[Zac Penn]

No Title

I am attaching a few pictures of my binnacle controls. It just has the center push button that allows you to throttle up without it going into gear. My starting procedure is as follows...
Squeeze the primer bulb many times until it is hard
Push throttle release button and move the throttle up slightly until I can feel the distributor to just rotate without opening the carb butterflies
Push in the key to bring down the choke plates
Turn the ignition so the starter spins for ever and eventually it will make a noise and then the starter disengages.
Release key and push in the choke and keep trying until it eventually starts. Usually it takes between 7-10 tries before it actually gets going.

Today I put some premixed fuel into a spray bottle and squirted once into each carb before trying to start. This had no effect on the cold starting so I don't know if the priming/enricher idea would work either. However my battery was a little weak this morning because I was fixing my tilt/trim system yesterday and cycled it up and down about 30 times and never tried to crank up the motor. The battery is brand new and is on the trickle charger now to top it off. I will try again later today with a fully charged battery and see if that helps.

 

[Chris1956]

Is there a black push button at the base of the throttle lever? If so, push it in and see if you have throttle only. Second choice is to see if the throttle handle pulls straight out (in this case, straight to the left), for throttle only.

 

[Zac Penn]

Yes I mentioned that there is a push button that will allow me to do throttle only. I just don't know how much throttle I should be giving the motor when I am cold starting it.

 

[ondarvr]

You position the throttle where ever it starts the best, it can be different with each motor.

 

[GA_Boater]

It takes more than you think, it's not like a car with a fast idle cam on the carb. Give it more throttle, it can take a higher idle when cold because oil pressure doesn't have to build like a 4 stroke. Keep nudging the throttle forward until you find the happy spot.

 

[Chris1956]

Advance the throttle lever a couple of inches and crank her. If the RPMs get above 1200, pull the throttle back until you get 1200 RPM or so....

 

[Zac Penn]

Okay boys and girls I got it all figured out A buddy of mine has a bunch of junk motors and happened to have an OMC 115 with a primer valve. He gave it to me so I spliced in a 1/4" barbed Tee right after the fuel pump and sent a pressurized line to the primer valve. I then used two .080" gas tubing lines for a weed wacker and zip tied them in place so they just stick into the carb face about 1.5" (just under the main jet tube that sticks up. I then tee'd off my choke power wire so that it powers both the choke solenoid (lowers the paddles over the upper carbs) and open the valve in the primer to shoot in some fuel.

I primed the ball, moved the throttle lever up about 1/3 and then push in the key for the choke and turned the key at the same time. It took about 3 seconds and she fired right up. Now that i know the principle will work, I can go about fabricating some actual nipples onto the carb so I don't have tubing sticking into the carbs

Thanks for everyones help in this!!!!!!!
Zac

 

[racerone]

When you know and understand how things work it is all " easy "----Just like toilet paper and #@# once you rip of the first piece the rest is easy.

 

[emckelvy]

Now that i know the principle will work, I can go about fabricating some actual nipples onto the carb so I don't have tubing sticking into the carbs

Zac, you don't have to run nipples into the carbs; all you need is to put a "tee" in the balance tube assembly on the front cover, and run your primer line to that.

As I recall, the balance tubes are 5/16" hoses but you'll have to check on that. They might be 3/8", I just can't remember.

You'll need a tee to fit the hoses, and with a smaller-sized barb to fit the size of the discharge hose from the primer.

The advantage to having the primer feed fuel right into the balance tubes is, this is a direct shot to the reed blocks, and you'll get the fuel into the motor much faster, and have a better start, than if you spray into the carbs, on the "air" side of the throttle plates.

And, you don't have to mess with the carbs at all, even better!

HTH.........ed

 

[racerone]

I install 4 nipples on the bypass covers.---Sprays fuel into the air just as it goes into the cylinder.

 

[Zac Penn]

Zac, you don't have to run nipples into the carbs; all you need is to put a "tee" in the balance tube assembly on the front cover, and run your primer line to that.

As I recall, the balance tubes are 5/16" hoses but you'll have to check on that. They might be 3/8", I just can't remember.

You'll need a tee to fit the hoses, and with a smaller-sized barb to fit the size of the discharge hose from the primer.

The advantage to having the primer feed fuel right into the balance tubes is, this is a direct shot to the reed blocks, and you'll get the fuel into the motor much faster, and have a better start, than if you spray into the carbs, on the "air" side of the throttle plates.

And, you don't have to mess with the carbs at all, even better!

HTH.........ed

Sorry for the long delay on this but I am back to this project.
Can you explain to me what those balance tubes actually do?
Are they normally just filled with air or is it filled with an air fuel mixture?
Does it matter where I place the Tee in the balance tubes? I have the primer mounted almost at the same level as the top carb so splicing in up high would not be a problem.
However going from a 5/16" Tee fitting and connecting that up to a .080" nipple on the primer is going to be difficult. Would it matter if there was a slight leak in this balance tube circuit? I imagine it would.