1999 225 txrx ox66

I recently had an ox66 honed and am attempting to start the motor after re-assembling. Gas mixture is 2x oil from remote tank.


The motor will crank and pop once or twice but doesn't turn over or sound like it wants to turn over.
I have pressure from the vst and can hear the top injector clicking. Injectors were just serviced. So, we have gas.

I tested the charger coil with a peak reading volt meter and it was high. Pulser coil tests at 3+.

I plugged in winky blinky but get no output.

Anyone have thoughts on what to try next. The pops I get sound more like a backfire. A quick "pak" and puff of smoke.

Re: 1999 225 txrx ox66

why did you have the motor honed?
Did you replace pistons and rings?
A motor has to turn over fast enough before it will crank(fire) up. make sure batteries are charged up

How do you get "Gas mixture is 2x oil from remote tank." This statement does not make any sense to me.

As with all motors you need good compression, good spark on all cylinders, proper timing, and then the right mixture of fuel and air to fire properly.
the 1st 3 are easy to test, then you are left with the fuel portion which is not as easy to test, but you can test fuel pressures and check that all injectors are getting pulses

Re: 1999 225 txrx ox66 2 stroke

Re: 1999 225 txrx ox66 2 stroke

I had a damaged piston in one cylinder with minor scoring. The cylinders were honed by a marine mechanic who was referred by a trusted friend/certified mechanic. New pistons pistons, rings and bearings were used.

By double oil from remote tank I meant that I was supplying 50:1 gasil from a remote gas tank and so had double oil overall.

I tested compression and all is 115-120.

With everything back together after the motor work, I had no start. I had fuel pressure from the vst and I ordered a peak reading volt meter to test the charge coil. While waiting for the meter to arrive I swapped the charge coil and stator and checked the injectors for functioning (injector filters had been cleaned when motor was apart). At this point I noticed the VST pump that had been appropriately pressurizing was silent so I swapped the assembly and we started up.

The boat ran well. We had one boggy return trip but all was well after swapping plugs (presumably due to oil). On the last run we seemed to run well but then topped out at 1800 on the return. Following that trip the motor would not start. I swapped plugs and it started right up but now is hard to start. It's back to spin at idle with a pop here and there. I crank strongly but no spark and only seem to turn over with heavy throttle.

I tested the charge coil and peak reading on the first two wires read 128v crank and 190v after starting. The second set or wires read 16v crank and 19v running. I swapped the charge coil and stator and had similar peak volt readings with high and low results on the two sets of wires.

The VST is providing appropriate pressure but it remains on when the key is in the on position.

Any help in next steps for trouble-shooting would be greatly appreciated. The numbers are off on the charge coil test but swapping the charge coil/pulser doesn't seem to fix. I am going to try another coil/pulser set as a triple check before proceeding, but am not certain what else I could try.

Re: 1999 225 txrx ox66 2 stroke

Re: 1999 225 txrx ox66 2 stroke

Deleted duplicate post.

Re: 1999 225 txrx ox66 2 stroke

Re: 1999 225 txrx ox66 2 stroke

Starting a few times the throttle has to be at least half open for it to start rather than cough a few times. When it starts it runs at a high throttle setting at about 1200 RPM. It runs smoothly like a retarded advance. It will pickup RPM after a few minutes and need to throttle down to keep the RPM from going way up. It will go through these two stages after six minutes.

Re: 1999 225 txrx ox66

Tested CDI output and it was way below spec. Swapped CDI and started right up.

Ran the boat and max RPM was about 2000 as it had been on the last run with ~2200 when pulling back on throttle a touch.

Checked throttle linkage and it allows full.

Checked VST and have 35 PSI pressure at dock (have not checked running yet). VST filter is clean. I will replace lift pumps even though these have been recently replaced, just to rule out. Ran motor from different fuel source. Vacuum gauge shows no significant vacuum in fuel line.

I'm curious what to check next. I can go back through ignition and fuel tests from the start. Curious if any ideas.

Re: 1999 225 txrx ox66

Giving numbers will mean something to others , not just saying Vacuum gauge shows no significant vacuum in fuel line and Tested CDI output and it was way below spec

Have you checked alarm system and timing?
motor limits RPM to about 2K when in safe mode even if your alarm is broken by retarding timing. Test to make sure it functions

Re: 1999 225 txrx ox66

Many thanks for the reply.

I've kept detailed records on the results so will be happy to share. I just don't have them in front of me right now.

99yam40 said:

Giving numbers will mean something to others , not just saying Vacuum gauge shows no significant vacuum in fuel line and Tested CDI output and it was way below spec

Have you checked alarm system and timing?
motor limits RPM to about 2K when in safe mode even if your alarm is broken by retarding timing. Test to make sure it functions

Click to expand...

Re: 1999 225 txrx ox66 won't run above 2200 RPM

Re: 1999 225 txrx ox66 won't run above 2200 RPM

Many thanks for the reply.

Charge Coil Test with DVA:
R/Br 190, B-R/L 19 Stumble and fail unless heavy throttle

Swapped coil and pulser.

Coil:
900RPM R/Br 200-230, B-R/L 169

Pulser:
17, 16, 15, 15, 15, 15

At idle it would spin or spin and cough but die. Motor would start at 50-100% throttle. It would rev and fade in a cyclical manner.

Checked CDI Output on the following cylinders:
1 17
3 18
5 67
2 14
4 90
6 18

Swapped CDI:

Immediate ignition.

Ran the boat:
No power above ~2000-2200 (perhaps 2300 with output above 2000 achieved by slightly pulling back throttle). Checked throttle linkage to make sure it was opening up.

VST:
Checked VST contents/filter and all seems well there. VST does not shut off after pressurizing when key in on position.

Vacuum:
Racor vacuum gauge at outlet side of Racor has not gotten above 2-3" Hg.

Alarm (possible RPM Restriction):
The key switch assembly was replaced a year ago. I am not certain all appropriate connections are aligned. They do not sound when motor is turned to the on position. Previous main oil sensor test signaled alarm. I will ground thermo sensor to test alarm. This will be fixed but my money is not on RPM reduction at this time.

I read testing procedure in manual and looked extensively online but cannot find a diagram to demonstrate the appropriate connections for the key switch assembly or a troubleshooting guide. I can test the switch to make sure it is functioning properly. It is relatively new and should be.

Re: 1999 225 txrx ox66 won't run above 2200 RPM

Re: 1999 225 txrx ox66 won't run above 2200 RPM

Seems every time I make a change that things start right up, then fall back to hard starting. May be a ground that has to be chased down.

From port to starboard I swapped the following components. Should the issue follow then I will narrow it down:
Flywheel
Stator
Pulser
Crank position sensor
ECU
Ignition coil tray
Ignition wires

The port starts up just fine. The starboard starts well again but a little rough in running at the dock. Will see how it runs when I have time.

Re: 1999 225 txrx ox66 won't run above 2200 RPM

Re: 1999 225 txrx ox66 won't run above 2200 RPM

HP pump not shutting off is a problem. But it seems the regulator is dumping fuel as it should. You're holding 35PSI right?

Re: 1999 225 txrx ox66 won't run above 2200 RPM

Re: 1999 225 txrx ox66 won't run above 2200 RPM

Tucker99 said:

HP pump not shutting off is a problem. But it seems the regulator is dumping fuel as it should. You're holding 35PSI right?

Click to expand...

Yes I look forward to figuring out how to get the HP pump back to normal operation. It is putting out 33 PSI at idle and under way.

I am seeing excessive fuel flow as evidenced by gas in the water and higher consumption on the fuel flow meter. The motor seems to slow down and then speed back up in a repeated fashion.

I checked the spark plugs and they were foulded so I changed them.

I rebuilt the LP lift pumps and replaced them.

I checked the TPS. It moves smoothly through the voltage range. While I don't understand reference unless that's the highest reading (5V), so don't have a number there but I pulled the side linkages and closed the butterflies to get .54V I snapped the side linkage back on and have .72V at idle. With the throttle down I am at 3.8V and have room to open the butterflies more to perpendicular if I adjust the throttle linkage further.

I set an aux tank with ring free shock treatment to decarb then set to warm up and test the oxygen sensor.

I tested the oxygen sensor and it read between .7 and .8V but did not move back down so I replaced it. Same results showing rich mixture being supplied without correction.

I tested the timing and it reads 7* +TDC.

I tested peak voltage from lighting coil and it reads 2.7V on both test harness connectors.

I tested the battery connection at the motor and have 12.4V at idle.

So, at this point I'm looking to back into the cause from the symptoms. The fuel is flooding, I have rich mixture at the oxygen sensor that does not subside and the timing has been adjusted to 7* +TDC. Anecdotally, it seems to slow down and speed up in cycles.

I could benefit from any help in charting the possible causes that map through to these symptoms.

Thanks!