1994 Mercury 200 xri warm start problems

[retooferab]

Still not dialed in. Realized when I set idle speed on the water I'd forgotten to loosen cam follower screw. I'm not sure what that affects, but will do it right next time. Also noticed this from another discussion when someone had, like me, set idle timing at 0:

back that idle timing up 6-8 ,0 gonna be rich as h--lllll, idle it up with air valve screw ... will idle much cleaner at 8 than 0, I like to run um clean as possible at low end for carbon purposes

It was indeed smoking and ran rougher the longer I idled. Will follow proper protocol and try what JOE said by moving idle timing more ATDC and countering that with more idle speed to keep it running (smoother? ...purring like a chicken?).

In other news, I finally saw the light on the whole .462 timing mark. Needed to get my hands on it; was WAY overthinking.
Now waiting for a longer plunger/tip for dial indicator so I can get pointer confirmed precisely and index all six. Good times. Really appreciate the wisdom here, and patience.

[scstarr]

my 94 200 xri has had the stabilizer bypassed runs great!

[retooferab]

Running great and not stalling with idle timing set at 8 ATDC and idle speed in gear 700-ish. Both of those screws (bolts) are set very near max travel which makes me a little nervous. Starting really hasn't improved so my plan is to test the temp sensors and (if needed) TPS...

In other news, my make-shift dial indicator/spark plug adaptor worked to finely tune the pointer. However, I neglected to make it work (have clearance) for other cylinders so indexing the other cylinders will have to wait for me to get the proper tool. I'll try to get the Jay Smith Racing tool as it seems most reasonably priced. Just mad right now that I wasted $40 on my own creation before discovering his.

[retooferab]

Though running flawlessly otherwise, my motor is still fussy starting, now both cold and hot. I tried starting cold with air temp then head temp gauges disconnected - no apparent difference. Tried warm start with head temp disconnected and it didn't like that at all (so I concluded it was doing something, probably correctly, and reconnected/left it alone.)

I do wonder if I over-corrected on idle timing (8 atdc) and if it's running too lean on cold start. Is that what sneezing means? Perhaps if I re-adjust that, my problems will be restricted to the warm start issue I started with.

MAP sensor ...revisited by removing the hose from intake orifice while idling. No change. Tried plugging the hose. No change. Tried sucking on the hose. No change. Had previously sprayed some cleaner in the orifice. Can't say I'm sure that did anything - too small for me to see - but looked clean. As I understand, MAP sensor is part of ecu and non-serviceable short of sending the ecu off for service ($$$).

Considering the motor runs great outside taking a few tries to start, I'll live with it these last weeks of season. Any way to pinpoint if MAP sensor is the problem other than process of elimination? Other tests I can do (on anything)?

[EuropeanAM]

Recommend:

Idle timing: 4 ATDC (lock it there)

TPS: .025-.028 VDC

Then set IDLE using the stop screw on the UPPER throttle blade (hidden behind the VST- long flat-blade screwdriver required).

With the fuels we are running today... you will eventually have to learn to crack the throttle open on WARM restarts. It's not the engine's fault... it's this junk we refer to as "fuel" that causes it.

[retooferab]

Thank you, I will do that and report back.

Is there a way to un-junk the fuel? Warm start issue may have coincided with a switch from Casey's 91 octane non-ethanol to Circle-K 90 octane non-ethanol. (Casey's stopped carrying it so now I have to drive to the next town to get non-ethanol.) In both I've been adding an ounce of quick-kleen and an ounce of quick-care to each 5-6 gallons.

[JOE54]

hard to find good fuel anywhere

[EuropeanAM]

Why are you running higher octanes? Has the engine been modified?

[retooferab]

Why are you running higher octanes? Has the engine been modified?

It's the only non-ethanol available near me. Engine is not modified.

Quick curiosity about TPS and ECM P/N...
"On models with ECM P/N 14623A15 and above ... adjust TPS to obtain readout of .240 - .260."
I've also seen "On models with ECM P/N 14632A15 and below, the TPS setting will affect start up."
My P/N is 824003 so I guess that's above 14632A15? Not sure how to factor in the letter "A"?

[JOE54]

824003 is above early ecu was .135

[retooferab]

OK, didn't get a chance to test due to a squall but here's what I did (still some TPS questions):
Idle timing is at 4 ATDC.
TPS is at .0253 VDC (I was surprised to find it at .0179 before adjusting; everything else on this motor has been spot-on. Time took its toll?
Idle is at 700-ish in gear.

My question/concern is here:

9. Slowly move throttle lever to full open position while monitoring voltage reading. Voltage reading should increase and decrease smoothly.
10. Set volt meter to 20 DC volts. Maximum voltage reading at full throttle is approximately 7.46 volts.

It increased and decreased smoothly, but full throttle was at 1.77 rather than 7.46. I'm open to the possibility that I am measuring wrong, but not sure how. This seems like a large departure from what is in-spec.

I also confirmed MAP orifice in manifold is clear.

[EuropeanAM]

Need to check your connection methods. Idle should be .25 VDC (+/- .05 VDC). NOT .025 VDC.

[retooferab]

It is adjusted it to .253 volts and I wrote it down wrong. Was .179 volts before I adjusted it.

Seemed to run a little worse - chugging in mid-range a tiny bit and took multiple tries to start both cold and warm. Unfortunately there were other variables affecting my impressions today: air temp was significantly colder at about 45*f and I was running a lower pitch prop because we chewed up the good one.

Plan is to double-check TPS and see what's up with that full-throttle reading. Not sure what else to do at this point other than, as previously mentioned, chalk up the fussy starting to junk gas and give it a little throttle when starting.

Re: idle timing, seems Joe is in favor of more atdc (closer to 8 or 9) and Don suggests 4 ...eh? Not that it's critical since I am idling fine without stalling at both settings since removing the idle stabilizer. Just curious what's optimal (oiler is still connected; not pre-mixing).

[retooferab]

Sharing my error and letting my pride take a hit so maybe it'll help someone and you won't repeat or have to admit the same mistake. When I checked TPS at full throttle, I wasn't anywhere near full throttle ...I was reaching over the motor and only had moved to max spark advance and not max throttle. Derp!

So TPS readings are close to spec at .24 key-on/idle and 7.5 full-throttle. Retarded idle timing to 6.5 atdc and set idle speed a hair less than 700 in gear. Also fine-tuned throttle cam just slightly to better align the mark with roller. Finally, put my good prop back on after being re-worked. Will see how it runs tomorrow.

[EuropeanAM]

That's more like what I would expect.

[retooferab]

I'm satisfied with how it ran today. Started, idled, and ran well. Ultimately, with all I checked and/or replaced, I think what made the biggest difference was removing the idle stabilization and detonation sensors (black boxes) then doing a precise timing/synchronizing/adjusting process per the manual. I settled with TPS set at .24, idle timing at 6.5 atdc, and idle speed around 700 in gear.

I'm slightly haunted by no change in idle with MAP hose unplugged, plugged, vacuum, etc. But I suppose if it wasn't functioning I'd see more symptoms.

Finally, I sometimes have a weird sound after starting (starter disengagement?), like a moan or low-frequency squeal, not sure how to describe it. Lasts 2 or 3 seconds. My google-fu has not turned up anything yet, and I'm left wondering if my starter is making the noise or what?. Not sure I'll get that addressed this year or not; my season will end soon and it'll be on to winterizing.

Thank you all for your help! Tackling this on my own kept me in-service and saved me money. Is there a way to donate to the site?

[EuropeanAM]

Try adding 1-2 drops of lightweight oil to the SHAFT of the starter (just below the nut). DO NOT oil the drive gear or it's clutch.

Sometimes if they're dry (or bearings are beginning to fail) they'll make an odd squealing noise as the drive gear teeth leave the flywheel.