Chrysler 70 HP 707HE Fuel Lines

Isa4325

Isa4325

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Can anyone tell me where these two lines go? The fuel line coming from the top of the fuel bowl has fuel coming out of it if I pump the fuel to the engine. That doesn't make since to me.

HELP PLEASE????????
 

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Nordin

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Isa.... the two hoses you point at are lines for the pulses from the crankcase which makes the pump to work.
The fuel pump has two stages hose 1 and hose 2 and it takes the pulses from the crankcase (underpressure/overpressure) to flexing the pump diaphragm forth and back.

If fuel comes out hose 1 when you prime the bulb then the diaphragm is bad..
 
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Isa4325

Isa4325

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Woke up this morning thinking the same thing, "Bad Diaphragm" both lines are vacuum lines.
Thank you Jordin for your input, appreciate it very much.
 
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Isa4325

Isa4325

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Jordin - Could I replace it with the newer style fuel pumps used around that same err and still have the four input lines that I do now?
 
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Nordin

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No, the newer style fuelpump does not use the two lines connect to the elbows,
The block that use the newer style pump has two holes in the casting into the crankcase.
 
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Isa4325

Isa4325

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Nordin said:
Isa.... the two hoses you point at are lines for the pulses from the crankcase which makes the pump to work.
The fuel pump has two stages hose 1 and hose 2 and it takes the pulses from the crankcase (underpressure/overpressure) to flexing the pump diaphragm forth and back.

If fuel comes out hose 1 when you prime the bulb then the diaphragm is bad..
Click to expand...

Turns out both diaphragm were bad, both had holes in them. Pulled all plugs out and craned engine over till the #2 cylinder was dry. Rebuilding the unit with new diaphragms and gaskets.
 
Isa4325

Isa4325

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Well I rebuilt the fuel pump and sediment bowl after cleaning it up thoroughly and mounted it back on the engine. Primed the fuel with no leas and reached a solid fuel pressure. Tried to start the engine only to achieve backfire in the exhaust. Timing is not right, but right according to the manual. Set TDC a 4*BTDC to achieve 32* at WOT. Turns out when set at TDC the #1 cylinder was NOT at top of it's cylinder, rolled #1 to TDC and had to create a new TDC timed the distributor checked if rotor was pointed to #1 spark plug pole, and it was. Key on, crank and choke, engine fires and idles at 1000 RPM, minor adjustment and idling at 825 RPM. Wrong fly wheel on this engine, which had to have been when the top end was rebuilt. TDC was scribed right over the carbs, and timing marker was mounted between the flywheel and top carb.

Is it possible the flywheel it self is marked 180* out of TDC?
Or the timing should have been at the rear of the engine and the timing marker is mounted in the wrong spot?
 
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Nordin

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Not possible the flywheel should be 180 dgr out of TDC.
Sometimes you have to readjust the timing marker plate if it has be off the block after a rebuild or soo.

The plate will be adjusted from the #1 piston at TDC, this is always the reference.

BTW you do not adjust the timing at 0 dgr TDC.
Always set the timing at WOT 30 dgr (or 32 dgr from manual) then the timing at idle will be what ever 2-5 dgr, it depends on the advance of the timing at idle (how much you need to open the throttle up to achieve a good idle speed).
 
jerryjerry05

jerryjerry05

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Change the plug wires around.
Sometimes fuel build up can cause a backfire.
Sometimes a vacuum leak causes a backfire.
The intake port covers need silicone to make sure they don't leak.

The last rebuild I did the motor coughed when trying to start.
It wasn't much but it blew 2 intake port side covers gaskets.
I saw a piece of one gasket, that's how I knew something was wrong.
It went from a small cough to a major backfire when the gaskets blew.
 
Isa4325

Isa4325

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Nordin said:
Not possible the flywheel should be 180 dgr out of TDC.
Sometimes you have to readjust the timing marker plate if it has be off the block after a rebuild or soo.

The plate will be adjusted from the #1 piston at TDC, this is always the reference.

BTW you do not adjust the timing at 0 dgr TDC.
Always set the timing at WOT 30 dgr (or 32 dgr from manual) then the timing at idle will be what ever 2-5 dgr, it depends on the advance of the timing at idle (how much you need to open the throttle up to achieve a good idle speed).
Click to expand...

Problen Nordin, when #1 is at TDC, the flywheel isn't. It's almost 180* out.
 
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Nordin

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Really odd ????????

#1... top cylinder?
Does the flywheel have a 0 dgr mark made from factory? or is it a home made mark?

It does not matter if the flywheel is from a 4 cylinder engine, top cylinder is #1 on those too.

As for using the engine it does not matter BUT you have to know that the 0 mark is NOT the 0 mark (TDC #1 cylinder).

Make your own 0 and 32 dgr mark, it will help you in the future and not confuse when checking the timing.


Just came up in my mind.
Has the flywheel the 0 mark at the outer rim (teeth for the starter)

The outer rim (teeth) is press fitted to the flywheel and it may have moved for some reason.
 
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Isa4325

Isa4325

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Nordin said:
Really odd ????????

#1... top cylinder?
Does the flywheel have a 0 dgr mark made from factory? or is it a home made mark?

It does not matter if the flywheel is from a 4 cylinder engine, top cylinder is #1 on those too.

As for using the engine it does not matter BUT you have to know that the 0 mark is NOT the 0 mark (TDC #1 cylinder).

Make your own 0 and 32 dgr mark, it will help you in the future and not confuse when checking the timing.


Just came up in my mind.
Has the flywheel the 0 mark at the outer rim (teeth for the starter)

The outer rim (teeth) is press fitted to the flywheel and it may have moved for some reason.
Click to expand...

Factory 0 mark with a arrow pointing straight up on the left side of the zero, almost looks lie a "10".
Yes 0 mar is on the outer rim inboard of the starter gears.

Out zeroed it in by running top cylinder all the way out close to the head then marked the starter gear, then I moved piston till it started its down cycle and marked the starter gear again, noted the center between those two marks as TDC. Three marks with center being TDC. Timed engine from there, 6* retard, making WOT 30* if I'm right. Soon to test on open water.

If the bottom cylinder in #1 I am timed 180* out.
 
Isa4325

Isa4325

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jerryjerry05 said:
Change the plug wires around.
Sometimes fuel build up can cause a backfire.
Sometimes a vacuum leak causes a backfire.
The intake port covers need silicone to make sure they don't leak.

The last rebuild I did the motor coughed when trying to start.
It wasn't much but it blew 2 intake port side covers gaskets.
I saw a piece of one gasket, that's how I knew something was wrong.
It went from a small cough to a major backfire when the gaskets blew.
Click to expand...

I am told that this engine fires 1, 2, 3 so I matched rotor to fire in that sequence.
 
jerryjerry05

jerryjerry05

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It is 1 2 3
Make sure it's set at the right plug?

The gaskets on the lower cyl.intake port cover seems to go first
 
Isa4325

Isa4325

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All gaskets are ok. BUT I found my problem with the 180* issue. The flywheel was 180* +or- out with crank due to a busted key way. Any ideas where I found a new Woodruff key for the flywheel/crankshaft?
 
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Nordin

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That explain everything.
Before replacing the key, lap the cranktaper with grinding grease such as Carbo Rundum.
Tight the flywheel nut to right torque, if not you will share it again.

Any Mercury dealer should have the key, many websites have it or Franz Marine.
 
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Derrick Fronckowiak

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Jerry, I remember from older posts that you (I believe it was you anyway) had mentioned that the key way is for flywheel to crank shaft alignment only and that it's the taper between the flywheel and the crankshaft (friction) that holds the two together and keeps them from turning (I also know this because I once under torqued my flywheel nut and it sheared the keyway (quickly). After I blended the damage on my crankshaft, I went to Ace Hardware and bought a few keyways (I love that store, they got all shapes, thicknesses and sizes of keyways-dirt cheap too). Since the keyway isn't "special" getting one from a hardware store (like Ace) should work fine, Right? Well, at least it did for me.
 
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