I REALLY NEED OX66 HELP! RodBolt? Cousin? Anyone?

[cedlin]

Alright, guys. I am having a rough time with my 1999 V200TRLX OX66 Outboard. Here is how things went down. I bought this boat from MN in April. I live in Colorado and brought it up to 5280 feet. The motor needed some maintenance so these are all the things I did.

-3 new LP fuel pumps
-Most filters, VST, On-board fuel filter, Water separator on the boat, (not oil filter)
-New lines from Water separator to engine
-New primer bulb
-New plugs, and Plug boots, (Tested resistance)
-O2 sensor looked terrible so I cleaned it up
-Cleaned out the High-pressure regulator screen

The last 2 weeks I have had this motor running like a top. Hitting high RPM's ~5300 with my 21 pitch prop. Yesterday, I took the boat up to an even higher altitude (7200'), changed the prop to a 19 pitch, and had a bear of a time with her running right. Felt like she was fouling plugs, missing, not gaining full RPM's etc. She took a while to get on plane and when she did, still didn't run quite right. The biggest problems were a surging and loss of WOT RPMs.

Now I am starting to put 2 and 2 together. When I took the boat from MN to CO, it had similar issues, missing, fouling plugs, etc. After all the work listed above, I thought I had fixed the problem. Take it up 2000 more feet and the problems are occurring again. I have not retested it at my normal altitude of 5280 since yesterday but I plan to tonight. The only other problem I have been having at either altitude is this. I can't get "warm-up RPMs" on the motor. It goes from 0 to 700 right on startup. No matter what the conditions or however cold it is. Then when I put the throttle into gear (forward or reverse) it ends up stalling. about 400-500 rpms and then dies out. Starts right back up, no problem, but dies for during slow speeds for whatever reason. (Think slow trolling a spot to look for fish on the graph).

So to recap my issues:
1) The motor doesn't seem to go to the Std. 1200 RPM warm up, just straight to 700 RPMs. Once it goes into gear, RPMs drop to 400 or 500 and typically stalls out. Motor starts back up fine and can be saved from a stall by pushing up on the throttle.
2)After taking my motor up another 2000' feet in altitude from running great at 5280', the motor was missing from the beginning. Ran rough, loss or WOT RPM's, and surging.

Here is where my thought process is at now based on everything I have already done on this motor:
1) Thermostats need to be replaced. It could be 17 years with the Original equipment (the LP fuel pumps were). Could that be causing my warm startup RPMS or idling issues?
2) I need to verify the TPS is working and in the proper voltage range.
3) Check the plugs for fouling (Would the extra HAltitude cause the plugs to foul? I thought EFI motors could adjust Fuel to air ratio on its own?)

Can the motors run Rich by default? Is there a way to sync the motor to work better in High altitude environments?

THANK YOU FOR THE ADVICE! I NEED IT BADLY!

 

[99yam40]

Rod has not posted here in years.
do a web search for Rodbolt17 to find him
but have you checked to see if the computer knows it has moved away from sea level or the last 2K ft?
check to see what it thinks barometric pressure is at key on motor off and it agrees with the closest weather station
O2 is less up high, so if the ECU thinks it is lower then it would be too rich to burn properly.

also you do realize that you will have less HP at higher altitudes right

Oh yea, make sure the ECU sees motor temperature properly

 

[cedlin]

​99yam40, Thank you for the reply. I was sort of leading myself to believe it was the ECU not getting the proper readings as well. Question is, I don't know how to check any of that on an OX66 given you can only use a winky blinky (I dont own one). Do you know of a proper way to check? I am aware of the elevation and lower HP. How do I check the temperature that the ECU sees?

My update for tonight is this. I checked my TPS using Rodbolts old post instructions. I was at .58 volts idle and then full throttle reading was 4.98 after I adjusted the TPS back to the recommended .62 volts. So needless to say, I think my TPS is fine. I also read some things about bad Thermostats causing fouled plugs. Well wouldn't you know, I removed both and they are stuck wide open. I am going to my local yam dealer tomorrow to get the replacement Tstats. I see how that could cause a rough idle condition and fouled plugs since the motor wouldn't be allowed to warm-up properly.

But I am still wondering why my motor won't go to "warm-up RPMs". I guess I will change the stats and see what happens when I hit the lake but I would think the motor would know to go up to warm-up idles until the temp is reached and then the RPMS would go back down to the recommended 730-750 out of gear, 650 in gear.

Any input on that? I think the tstats will be a HUGE step in the right direction. I'm just not sold that solves everything.

 

[99yam40]

I agree,

I see you found Rod and he answered you on the other site
I was thinking if the ecu already thinks the motor was heated up then it may not go into the cold warm up, but I could be wrong.
I am sure there is something written somewhere that would say what Ohms a sensor should be at a certain temp., but I have not idea if you motor has a sensor or switches like my C40 that tell it the motor has warmed up.
Rod is the one that can give more info I am sure.
and he should give info on reading barometric also
Like Rod said check timing to see where it is at at start up and after it has warmed up, my C40 adjusts idle speed RPMs with timing also