Logo
FULL SITE MENU

2003 md50b questions

O

oneeyemike77

Contributing Member
I'm going in the morning to look at a pontoon with a 03 md50b on it. I have had a few outboards and have done quite a bit of work on them ( always get manuals as i will for this one if i get it) but this one has me concerned because I have no expierience with these motors. From what ive read there is a way to check for codes on these motors and was wondering other than the normal things to look for, what else should I look for. The boat is not near a lake but owner said that i could hear it run on muffs. Planning on checking compression hopefully if possible. Motor did spend the first year or so of its life in around saltwater and that concerns me too. other than just cking for corroded bolts and such what else should i be looking for?? thanks for any help
 
Just the usual. Check compression, verify telltale, etc. The TLDI is a complex DFI motor, so running diags (using the Factory service manual as a guide), the ECU can tell you whether any errors have been recorded, as well as recent running conditions. As with any oil-injected motor, be sure to bleed the oil system if the motor has been sitting for a long time.
 
I bought it. motor started right up and runs but no water coming out from up top, im assuming that the white nipple sticking out is where it should come from. Compression was 125 on all 3 cyl. I want to check water pump but dont have manual yet, i will order one this afternoon, is there anything special to do or should i wait on manual... i have changed many water pumps before but dont want to get over my head before i get me a manual..
 
Any Tohatsu/Nissan dealer can help you; even me. Get 003-21050-2, $40.00 for the Tohatsu flavor, or 003N210502 for the Nissan flavor.
 
Got manual and got lower unit off and checked impeller and it was melted to pieces. I checked codes and it had 13 stored. Everything from abnormal high water temp(duh!) , TPS, FFP, Bad coil, CPS, Low voltage, and more. Checked thermostat and flushed and Replaced waterpump, drained all the oil i could from tank and replaced , checked oil filter and bled system. Fresh gas and fired it up and ran it for about ten min. Motor was peeing and running a little rough. Now i only have one code that there is a bad #2 coil and plug. Will check out more tomorrow but figure i will get one coming. This thing dont smoke at all. I read about the tldi process but no smoke at all?? Is there a way i can check to make sure it is getting sufficient oil? I hope since it only has 150-250hrs and has 120 compression on all cyl it will still be a good motor. anything else i need to check?? Thanks in advance for your time
 
Got to work on motor today and checked every oil line coming out of the pump and no oil in them. There should be oil in them ...right? Ran motor again for a minute again and checked lines... no oil. Yes i cleaned and refilled oil filter and yes i bled the pump repeadedly to ensure no air. Does this mean bad pump or could it be something else?
 
I got the factory manual. Yes I did just replace the impeller as my local napa had a Sierra in stock. I am going to order the whole kit before I take it out. I took the outgoing lines off top of pump an no oil coming from any of these. I did not find much info in the cam about oil pump, just how to replace. Do they fail much? I tried force feeding it for a few moments but saw no oil and got scared about the air compressor and motor getting oil... Will it hurt anything if I do run for 30 min at idle like it says...will the air compressor get damaged if no oil is going to it.. Also don't remember seeing gps reset but I will look when I get home. Thanks so much for the help
 
If you have the Factory service manual,

003-21050-2_lg.jpg

please review the section on setting the Throttle Position Sensor to zero.
To do the force feed, you disconnect the pump rod and allow the pump to run at 100% while idling. The air compressor should be OK if you just idle.
The complete wp kit is available from any Tohatsu/Nissan dealer... even me... a good place would be the dealer who sold you the manual.
The oil pump on those is rock solid. I have never changed one.
At idle, the ratio is more than 150:1, so likely little if any smoke.
You could fill the oil lines manually to speed up the process, if you are so inclined.
 
Force fed the motor for 30 mins like you said and sure enough there is oil flowing. Now hopefully all I need to do is get a new coil and there will be no more lights flashing. I plan to put the whole waterpump kit in as well. Thank you paul for taking the time to share your knowledge. I will keep you posted.
 
I found the specs for the coil in the book and I have both a cheaper analog meter and a fluke digital and sort of confused about how to do it . I understand the secondary resistance between the plug cap and ground?? But the primary resistance wire colors that the fsm lists are different than whats coming out of my coil. Have a black , white , and blue coming out of my coil. I feel silly that I cant figure this out , going to study my manual.
 
My brain worked a little bit better today and again Paul you have saved me buying a part that wouldnt have fixed my problem. Primary and secondary resistance checked out fine on all three coils. So I checked codes again and this time in addition to the #2 coil and spark plug code it now has a CPS code stored as well. So I erased the codes and decided to reset the TPS since I hadnt did that already. It cranked up and ran normal for about 30 seconds and died never to fire again. I tried a couple of different times about 15 min a part to crank it up this evening and it never fired except for a few pops and coughs. Thinking and hoping that i have flooded it I quit this evening relieved that i didnt needlessly buy a coil but now worried that i have messed something up. I did read the codes again and all it has stored is #2 coil and plug ... no cps. I looked at the wiring for obvious damage but see none. Dont really want to go messing around with things and create more problems but not sure what to do next. I noticed that the wires from the coils go to the black plug on the computer in the scematic but i dont want to unplug it as im scared of messing the ecu up. Going back to the book scratching my head....
 
Always check the plug connectors. Clean contacts as needed. You can add Lanocote to any connectors to reduce future corrosion issues. Don't overlook grounds, especially on TLDI motors. What do the plugs look like?
 
The plugs look good to me but I think I will go ahead and get a set anyway as it couldn't hurt. Is there any danger in unplugging the black connecter on the ecu that those lines run to... Could this be a problem on the instrument panel as the console is going to be replaced because the dash has deterorated . The gauges have sort of fell inwards a little... I didn't want to mess with that end until I got the motor running right but no I'm wondering if it .could it be on that end??
 
Did get a set of plugs today per factory specs but it rained me out this evening. I did manage to catch a break and give it a try just to see if it would run at all. Again nothing. Almost like the kill switch has messed up. Could i have damaged it resetting the TPS. It has run with no troubles until i reset the TPS. Hopefully will get a chance to work on it in the am for a while and check some connections and grounds, as i will be going out of town for the weekend and wont be able to work on it this weekend. Feeling like Im going backwards now.....but im gonna get it
 
Every bit of testing is valuable diagnostic info. You can test the stop switch. Don't get discouraged at this point.
 
Checked all rhe connections and didnt see any visible corrosion and all seemed good and tight. Pulled the plugs since I hadnt done that since the force feed. They were wet so I went ahead and replaced them and gave it a try. It fired right up and let it run for a minute or two..... no flashing lights!!!! WHOOO HOOO!!!
Paul, again thank you for all your responses. Your knowledge and guidance has saved me from needlessly spending money that i didnt have. I went out on a limb and bought this pontoon for my family even though we had a vacation planned this weekend. It has taken a tremendous load off me to be able to leave knowing i got a motor that runs . Thanks again Paul.
 
Back
Top