How to de-pollution a X-flow ? Just got one for the boat :)

[addo]

Funnel? That's what the woman got bit on. Remember that newsreader's Freudian slip? A woman is recovering in hospital after being bitten on the funnel by a finger-web spider.

Actually I think it's where he pours the starting fluid (rum). It's a marine engine, and we know what Winston Churchill said about mariners' traditions...

 

[Anonymous]

Red goes to the + on the coil, and this terminal also gets 12V supplied to it. Use a good gauge of wire. Green goes to negative on the coil. Only other wire off the negative coil terminal goes to the tacho.

Sounds exactly like your picture looks, except Addo didn't mention a funnel

Oh crap - you're right. How did i miss that !!! :x

Funnel ? Yeah yeah its a crap diagram i know...

 

[Roath]

Great thanks L6

It's taking me a while, but I think I'm finally there! (bit thick you see)

So going off this as a timing 'curve'

Since my top revs is a just over 3000 RPM I would remove my vaccum and adjust my timing as if the engine was cruising at 3000 rpm. So roughly that would be about 8 degrees. This finally means I can set the timing at 14 BTD (8 + 6) at idle?

This would give me more power at 3000 but use more gas right?

As before thankyou

 

[L6]

See immediately below the heading CENTRIFUGAL the text reads, “Distributor r.p.m. Advance degâ€￾.
This means the figures listed are the RPM and advance measured when the distributor is in a test machine. When installed in an engine the distributor turns at half the crank speed, so the figures here have to be doubled to convert them to crank revs and crank degrees.

The figures below the heading VACUUM, show the advance (in distributor degrees) for a range of manifold vacuum and these are completely independent of speed. Ignore these for the moment; the typesetter has caused confusion by placing the centrifugal figures and vacuum figures side by side to save space.

If you blocked the vacuum, and then set the initial timing at 6degrees, and the distributor curve is perfect, you would then expect a timing light to show the following.

RPM Timing BTDC
500 6+0 = 6
1000 6+2 = 8
1600 6+9 = 15
2000 6+14 = 20
3000 6+21 = 27
4000 6+28 = 34
4600 6+32 = 38

You could be a fusspot and check the timing at every engine speed listed in the table above, however the only really important place is at the revs corresponding to max load, which is the engine RPM when the throttle is wide open and the boat is at full speed. From the text I believe this is 3000RPM for your boat.

With the drive in neutral and the vacuum plugged set the recommended idle advance, then bring the engine up to the revs for max load (3000rpm for your motor), read the timing, and compare it with the factory figures above. If they are the same that means the timing curve in your distributor is perfect. If as I suspect they are not the same then adjust accordingly (27 degrees for your motor). The timing will only be correct at max load, but who cares.

After setting the centrifugal timing you can reconnect the vacuum line if you like but it will have almost no effect, as it is only effective at high vacuum which corresponds operation at part throttle, and this hardly ever happens in a boat.

Note. The maximum advance shown in your manual is about 10degrees more than I would have expected for a motor of this size, so timing markings to 30degrees as I had suggested in an earlier post are a bit mean for anyone running up around 4000RPM and it would be better to extend the marks up to 35degrees BTDC.

 

[Roath]

Hi L6

OK, much easier than I thought. I admit to have completely lost the point now. Aside from perhaps being less to go wrong I can't see the advantage any more. :

I think I will just chalk this up to being a dumb c*nt and just go ahead and doing it.

Thanks heaps and I will leave you alone now.

 

[L6]

Hi L6

I admit to have completely lost the point now. Aside from perhaps being less to go wrong I can't see the advantage any more.

This is the reasoning.

After a distributor has been in service for some time, the springs stretch, the cam wears, and parts are often swapped so the advance curve rarely matches the original specs.

Most people simply set the initial advance at idle and remain oblivious that the timing at other speeds is off spec. This means the timing is accurate at idle where it does not really matter, but could be miles out at the revs where it is important.

I am suggesting you should make the advance correct at the critical revs and ignore where it falls at idle.

Why is this more important in a boat? If the distributor is over-advancing there is high likelihood of detonation. In a car detonation is easily noticed and the engine only operates at full power for short periods, but in a boat detonation can be masked by open exhausts and over long periods at full power this will destroy the engine.

 

[Roath]

Thanks L6

I was kinda lost at comparing the timing of a motor cruising at 3000 rpm and a motor at 3000 rpm WOT and thinking that this the thing we were trying to compensate for.

Sweet, so is short it is basically just less to go wrong. With no vaccum advance we don't have to worry about the vacuum advancing the timing any more. (at WOT) and basically doing the timing at 3000 rpm's is just checking the centifugal advance is working correctly.

Looks like no rain for the first time in ages today so I may just give it a go. ( timing on the driveway). Hamilton Jets don't have a neutral so I have to unbolt the jet and run the hose through the heat exchanger...

Thank you for your patience

 

[L6]

Hamilton Jets don't have a neutral so I have to unbolt the jet and run the hose through the heat exchanger...

--forgot you had a jet. No mechanical neutral is a pest, even with the boat in the water and the bum plate halfway down it is not practical to run the motor up much over an idle.

Saw one guy unbolt the jet unit ---at the jet end the jackshaft.