1994 Mercury 200 xri warm start problems

[retooferab]

Serial# OD270639
1994 Mercury 200 xri (EFI) 2.5L

Symptoms: Motor has been increasingly hard to start (and idle) when warm. Starts and idles ok when cold (first start). Runs great except for fussy starting and at or just off idle when warm; also a little smokey at start/idle. Will start warm with slight throttle in neutral but have to be gentle coming back to idle or will die. Cutting power abruptly causes a stall.

What I've done so far:

• Replaced fuel lines, in-line filters, bulb, fuel/water separator. Eliminated quick-connect.
• Rebuilt pulse/low-pressure fuel pump.
• Replaced check valves under VST and in crankcase from oil tank.

On my to-do list:

• Check and clean final filter near fuel pressure regulator (any tips??)
• Check fuel pressures (at what times/RPMs??).
• Check vacuum at fuel pressure regulator (how??)
• Check temp sensors (how??).
• I keep reading about the link-n-synch but not sure how to find procedure for my motor.

Advice?

[JOE54]

disassemble regulator,all rpm, vac gage,can be done with ohm meter, purchase a genuine merc serv manual for your engine,check bleed system throughly as well as test all sensors air temp for sure

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Thank you, JOE54! I will do all this asap. Just cracked some ribs this morning, though, so there will be a delay till I feel like moving.

[leonreno]

Ouch!

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A couple thoughts while I'm still laid up.

1. Mercury Service Manual is amazing! I think I'm mentally prepared now to address my list and what JOE54 added.
2. What about the Idle Stabilization Module? Seems a bad one would result in the stalling problem I'm having - not sure about the warm start problems. I'm not against "simplifying" my motor but are there ANY downsides to removing this box? Off-idle or part-throttle drivability?

Any guesses what the problem will ultimately be (and why)?

• Clogged final filter?
• Bad fuel pressure regulator or leak before/after regulator?
• Bad temp sensor (which one)?
• Link-n-synch out of spec?
• Bleed system leak?
• Idle stabilizer module?
• Other?

I sincerely appreciate your attention to my problem even though I'm unable to do much yet. Cracked ribs suck and I'm losing my mind not being able to tinker. Hopefully in next few days I'll be able to move more. And barring death or disability, I will not abandon this discussion!

[JOE54]

leave that module on there for now , test all sensors and be sure you do not have a leak in intake plenum

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Thank you. Will I detect intake plenum leak by pressure and vacuum testing at fuel pressure regulator, or how? Any tips for detecting bleed system leak?

Timing question following this excerpt from service manual:

Model 200 XRI
Full Throttle RPM Range 5000-5800
Idle RPM (in Forward Gear) 625-725
Maximum Timing:
@ Cranking Speed 16° BTDC
@ 5800 RPM 22° BTDC
Idle Speed/Pickup Timing 0°-9° ATDC

STATIC MAXIMUM TIMING ADJUSTMENT (CRANKING ENGINE WITH STARTER)
... Hold throttle arm so that maximum spark advance screw is against stop.
Crank engine with starter. Adjust maximum spark advance screw to set timing to attain appropriate setting...

What's the "appropriate setting" at this step?
I thought it would be 22° BTDC but now second-guessing 16° BTDC because I’m only cranking during this static adjustment. 16? 22?
(Might be obvious once I'm at the boat; doing everything I can from couch at the moment.) Will I only see the 22 flying down the river at WOT?

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Kind of on my own here (HELP anyone?), but documenting for posterity I suppose. Might help someone someday...

• Cleaned final filter (though it wasn't particularly dirty). TIP: Either don't mess with the o-ring in filter or have a new one handy. As soon as mine was out it was clear that it was swollen (diameter) and not wanting to fit back in the groove. Freezing it overnight and delivering to the motor in a cooler allowed me to re-install.
• Cleaned orifice where MAP hose goes into manifold. Again, not noticeably dirty, but shot it with some Mass Air Flow sensor cleaner anyway.
• Checked fuel pressure - in spec throughout (36-38).
• Checked vacuum but not sure what I was looking for. May have been loose fitting, but I got 7 at idle (didn't look beyond idle).
• Checked bleed hoses and fittings (visual and squeezing/tugging). Seemed ok? Still not sure how to test.

TESTED Idle Stabilizer per the manual. It does NOT appear to be working. There was no "rapid spark advance" as engine slowed to below 550 RPM. I could retard the timing down to where it wouldn't run. Also tried in gear and killed it when retarding timing.

"TEST FOR PROPER FUNCTION OF IDLESTABILIZER
IMPORTANT: Due to the sensitivity characteristics of individual modules and tachometer variances, the engine RPM at which the module willadvance/retard the ignition timing may varyslightly from specification.Connect a timing light to No. 1 spark plug lead (top,starboard bank). Start the engine, and allow it to idleabove 600 RPM, then retard the ignition timing byslowly pulling forward on the spark advance lever.Observe that the system is functioning by noting arapid spark advance (as much as 9°from the idle setting) as the engine slows down to below approximately 550 RPM.The idle stabilizer is not repairable. Should the idlestabilizer fail to function as described, it will requirereplacement."

By the way, idle timing was about 6 ATDC.

Before I test temp sensors and do a complete link-n-synch, doesn't it make sense to replace or bypass Idle Stabilizer module?
IMG-3099 (1).jpg

[Mike_in_NY]

I had a 95 200 XRi and I had the exact problems you are having. I tried everything and it wasn't until I scrapped the idle stabilizer and timing advance module that I finally got rid of the issue. I set WOT timing at 22 degrees (you can go to 23 safely) to be cautious and idle timing was adjusted with boat in the water. I don't remember the exact number but think it was 4 degrees ATDC. All you need to do it is a dial indicator, timing light and a jumper for the switch boxes. For me, it made a huge difference in idle quality and overall performance.

[retooferab]

Mike in NY! Thank you for the response! Do you remember specifically what you did with wires after removing the module? I'm not sure what to jump, connect, disconnect, etc. From what I've seen here on bbc, it's different for different motors.

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Can someone (Mike? Joe? Don?) please confirm the below quote is 100% accurate for my motor? It's from this thread regarding a 1994 200 XRi but there is no serial number there.
http://www.bbcboards.net/showthread.php?t=277425
I want to be sure this advice holds true for my motor (see pic in previous post and serial # in original post).

Physically REMOVE the module, disconnecting all of it's wiring.

A white w/black stripe JUMPER wire must be installed between the two switchboxes (on the posts that previously contained white w/black wires). This is the BIAS (timing control) circuit... and the two switchboxes MUST be able to interact through the jumper.

One gray w/white stripe wire (formerly attached to the advance module) must be affixed to a GOOD ENGINE GROUND.

Set timing STATIC... I'd recommend 23 BTDC at cranking speed (or better yet, index all six cylinders with marks on the flywheel, and verify that NO CYLINDER EXCEEDS 25 BTDC).

[JOE54]

thats it

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Thank you! Couple timing questions:

1. To index all six on flywheel, are the marks at the same .462 as on #1? (Sorry for dumb question: my understanding of timing is very basic.)
2. The manual says to set max timing adjustment on the water at 2500 RPM. Is that because timing stays the same from there on out? Or because they don't want the liability of us falling out of our boats at top speed? I can find a long stretch of smooth water to do it (at least check it then adjust/repeat as needed) at 5800 RPM if it's better.

[JOE54]

index 0 on all 6, set it static at 23 , or on trailer at ramp with test wheel

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Idle stabilizer is out but instructions aren’t adding up re: wires, jumping, etc. My module has three wires: white w/black stripe, red w/white stripe, black (ground). The white w/black stripe (after bullet connector) was spliced into one of two other white w/black stripe wires going from each switch box to another black box (detonation module?). So when I unplug my idle stabilizer module I have an empty red/white wire from outside switchbox and two white/black wires (one from each switchbox) going to the detonation module. My inclination is to just plug the connectors and leave it. Since white/black still are connected through detonation module. Any need to add jumper or do anything else?

[JOE54]

ok cut the blk/wht wire at the junction long enough to connect to front box put a ring terminal on it remove red/wht stub wire from frnt box and remove all else grnd gray/wht from harnesswasnt so hard was it

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Thank you, JOE54! It's running good, at least on today's test drive. Fired up instantly every time and idled fine. Will see when I put it through a normal outing.

• Removed Idle Stabilization module.
• Set idle timing in water (2 ATDC).
• Set idle speed (700ish).
• Set max timing in water (22+ BTDC).

Unfortunately, my dial indicator was not up-to-task so I didn't re-set timing pointer or index all six cylinders.

Also checked the detonation control...

DETONATION CONTROL (200 MODEL)
With outboard running in “FORWARD” gear, advance throttle to 3500 RPM and check that spark timing has electronically advanced timing to 26°BTDC. This indicates knock control circuit is functioning.

No timing advance was evident. Maybe this is for the 200 PRO MAX/SUPER MAGNUM and not my XRi?
(And what's up with 26° BTDC? I thought these motors grenaded at anything over 25°)

In any case, I'm hoping I'm good to go! Will be back if any related problems or questions come up. Thank you, all!

IMG-3126.JPG IMG-3128.JPG IMG-3130.JPG

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Remembered later I never re-connected my (apparently inoperable) detonation sensor after setting timing. So my successful "test drive" was with it disconnected (or at least not sensing). Now I'm thinking I should yank that module off as well so it's not meddling with spark advance, double-check timing, and motor away happily (really can't afford to melt this motor). I believe it's in this case I'd need to jumper the BIAS terminals and ground the grey/white wire from ECM. Eh?

[JOE54]

exactly post#16, if your leaving oiler hooked up only need warning module

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Ran it today and stalled out at idle so I turned up idle speed on the water then played with idle timing and idle speed back on the lift. Ended up with idle timing right about TDC (0) and idle speed 700+ (just reading my dash tach and not sure about accuracy). WOT timing is around 22.5 BTDC. Hoping tomorrow goes without stalling. Attaching a couple pics, one of missing modules and another showing the jumped BIAS terminals and grey/white grounded at bottom corner of switchbox.
IMG-3142.jpg IMG-3144.jpg