Merc 150XRI Full Throttle and oiling problem

[engdocpro]

Recently installed a 1995 Merc 150XRI recd from reliable source. Excellent compression exactly 130 across all cyls. After some ironing out issues motor ran perfect for the summer until last week. When approaching the last 20 feet to the dock after good day out, the alarm went off but fortunately I was able to shut it down within about 20 seconds or so.. Long story short, the motor is not oiling (no smoke at all). I know about the plastic gear, etc. but I didn't want to pull the pump at this time to confirm. I attached aux tank with pre mix so that I could run the engine, which seemed fine except for the alarm, revved up good, etc. I disconnected the tan/blue wire coming off the low oil warning module and all seemed well. Topped off my tank with pre mix fuel and reconnected the fuel line to the engine direct as usual. I put the boat in the water and all seemed fine. I have a very long no wake zone so I was able to get the engine warm and left the top off so I was able to check the temp of the cyl heads. When I was finally able to open up the throttle, the Eng. went to approx. 1500-2000 rpm, completely bogging down. I retried a half dozen times, same response. Idles "OK" , doesn't stumble going into gear, but will not rev up. Back to the dock, check my plugs, nice color and slightly wet, looked all over but couldn't find anything apparent wrong. I've been rebuilding engines all my life (not marine), but have ZERO experience with electronic components. Seems to me that the computer is either shutting off the fuel supply or not allowing any advance at all. I Tried reconnecting the alarm wire, no change. Still revs fine in neutral. I have a dozen ideas but don't want to just throw money at it because that never works. Thanks in advance to anyone that can help, Dave

 

[Dukedog]

pm me an email addy and i'll send ya a coupla oem manuals in pdf.. ecu doesn't do as much as ya think!.. sounds more fuel related but could be 'lectric.. pull cowl and listen for 'lectric fuel pump when key is turned on.. should run 'bout 30 seconds then shut off unless ya start tha motor... ya might try pumpin' tha bulb when its in tha "bog mode".. jus one way to test mech. fuel pump.. any runnin' test need ta be in tha water under a load... most things won't really show up on tha hose....

 

[engdocpro]

engdoc39@hotmail.com, Thanks. Elec fuel pump does just like you said. As far as fuel supply, I have an 2-3 psi elec aux fuel pump hooked up to reg on-off switch on board because of problems with my old motor. That doesn't help either. Alarm sounds steady but if you listen carefully, it does pulsate a little. some guys who have heard it say its steady, others say its beep, beep, beep. I would say steady. I opened the bleed hole on the oil pump while Eng. was running and it does seem to put out a medium to week stream of oil. Not sure if that really means anything. I was going to throw an overheat sensor at it. Also, someone told me to disconnect the low oil module altogether, not just the alarm wire but I'm reluctant to do that. Thanks for your help.

 

[Dukedog]

sent.. lemme know if ya get 'em?
ya already have over heat sensor and alarm... starboard head, under #1.. ground that tan/blue.. ya should get tha "solid, loud buzzer" (key on)... any other sound tha buzzer makes other than that means its tha oilier module sendin' tha signal.. thats tha sole reason for tha module (plus self check beeps when key is turned on)...it makes any input signal modulate... jus so happens that over heat and oilier share same buzzer but thats it...... modules DO fail and odd sounds and/or absent of are an indicator of it... but will not cause what you describe with tha "runnin'" problem... manuals will tell ya how ta test each sensor (low oil, rotation, water) from module....

ecu really only controls fuel delivery... only "electrics" controlled by ecu are tha injectors and fuel pump.. will not shut anything down if "anything else 'lectric goes away, ie: trigger, stator, regs, coils, timing and etc with no control over any of 'em.....

get inta manuals and bet ya figure it out... probably easier than us "guessin' on tha keyboards".....gl.

one other thing that can cause problems with runnin'/timing.. advance/idle stablizer module.. give it tha "float test" and don't worry 'bout it anymore.. its not a necessary item.....

 

[engdocpro]

Thanks. I went down to the boat this past Saturday. Its 30 miles to the marina so I cant go every day. Anyway I was kind of obsessed with seeing if the oil pump was actually working so I pulled it out and, yes it is. This is a big relief to me because at least after I find out the reasons for all the other stuff, I know that that dumb idea of a plastic gear on the C/S is still good. I'm fortunate to have the owners of the marina occasionally come by and give me suggestions.(I've been there for about 20 years). He suggested I check my spark, saying he's seen this before. I didn't mention that I had changed my regulators because it was putting out erratic charging and was told that I shouldn't run the engine like that because it would damage the stator, which I understood. he also told me to change both of them. I did that and everything was hunkey dory (when's the last time you heard that one?) for about a month, until I started to have this oiling problem SO, I pulled the plugs and come to find out the only one bank is firing!!! Looking at the manual led me to the switchbox and then to the stator and flywheel. I didn't even need to do any testing because I found a piece of magnet sticking out and rubbing on the stator, which in turn made my eyes to see large dollar bills for a while. I didn't have the proper puller with me so I haven't yet removed the flywheel or stator. I guess they were right, the my stator did get damaged, probably made the winding swell and hit the magnets and it took a month to fail altogether As soon as I get my puller and take things apart and locate some replacement part, Ill let you know how I made out. Thanks, Dave