1989 mercury 150 black max xr4 oil issue

[gschultz05]

good evening i have a 1989 20' cheetah limited surface tunnel boat with a 150 merc black max xr4, compression is 140 across the board, we had just got this boat about 2 weeks ago, boat runs great on the hose but previously under load it would collapse the primer bulb, since fixed. Boat has had the oil alarm go off since we have had it, the replaced the oil tank cause the connection was leaking on the cap, put good crimp clamps on all the lines on the engine since they had a small leak before, purged the emergency tank so its topped off. The alarm will sound once the motor gets to about 4200 rpm or above, if kept below that its stays quite and can just put around. looking for idea on what it could be? another thing is the boat will barely rev to around 5k rpm maybe a little more, we had an 87 black max before and that thing like to go. Not sure if this one is over propped or what but it dont go like it should.

 

[Dukedog]

do you get tha self test beeps when key is turned on?.. is tha alarm over 4200 oscillating beeps or a solid, continuous beep?..

 

[gschultz05]

do you get tha self test beeps when key is turned on?.. is tha alarm over 4200 oscillating beeps or a solid, continuous beep?..

Yes I get the beep when ignition is turned on. Alarm is a beep-------beep-----beep, it isn't the solid temp beep

 

[Dukedog]

there is a green wire (rotation sensor) coming from tha alarm module going to bottom terminal of one of tha switch boxes along with another green going to one of tha coils.. disconnect it (module side) and test.. you may have a switch box going south.. this would explain it being down on power also...

 

[gschultz05]

there is a green wire (rotation sensor) coming from tha alarm module going to bottom terminal of one of tha switch boxes along with another green going to one of tha coils.. disconnect it (module side) and test.. you may have a switch box going south.. this would explain it being down on power also...

With that wire disconnected and when tested, if the alarm don't go off then that tells me the switch box is bad or going?

 

[Dukedog]

it would lead me in that direction but cannot say by justa computer conversation....

 

[gschultz05]

it would lead me in that direction but cannot say by justa computer conversation....

I understand that, I may just pick up some switch boxes and see if I can fund that sensor

 

[Dukedog]

tha sensor itself is a magnet setting on top of tha oil pump boss.. it reads rotation of pump drive gear and coordinates a reading between it and tha firing of tha cylinder from tha switch box to produce a signal to tha module.. doubt its bad... some say you can move tha green coming from tha module to another terminal on tha switch box.. don't know if it does or does not work.. i always disabled tha oiler and went ta pre mix myself..

 

[gschultz05]

tha sensor itself is a magnet setting on top of tha oil pump boss.. it reads rotation of pump drive gear and coordinates a reading between it and tha firing of tha cylinder from tha switch box to produce a signal to tha module.. doubt its bad... some say you can move tha green coming from tha module to another terminal on tha switch box.. don't know if it does or does not work.. i always disabled tha oiler and went ta pre mix myself..

the sensor and ball look fine, I just decided to not mess with it and be done and ordered a delete kit so I will just eliminate that problem

 

[Dukedog]

good idea... but you may still have a bad switch box if its down on power.. with all things right ie: gearcase, prop and motor height it should turn close ta 5800 or more on tha right hull.... not to familiar with cheeta.. what type hull?.. weight?.. may be a little short on hp for a 20 footer?.. is it similar ta say the stoker?

 

[gschultz05]

good idea... but you may still have a bad switch box if its down on power.. with all things right ie: gearcase, prop and motor height it should turn close ta 5800 or more on tha right hull.... not to familiar with cheeta.. what type hull?.. weight?.. may be a little short on hp for a 20 footer?.. is it similar ta say the stoker?

I'm not to familiar with cheetah either, it's my first one, not sure on the weight, it is called a limited surface tunnel hull, inwas talking to the local boat shops and both shops had said that the 22 pitch prop was to much and it should be 19 to 20, so I ordered a 19. Also the boat originally had an extension on the rear for the motor but previous owner removed it so that changed the dynamic of the boat and its original set up. I'll delete the oil injection and try this new prop and see what it does, the 19 should bring my rpms right around they need to be

 

[Faztbullet]

The only Cheetahs' I have see are tunnel style deck boats and never seen a outboard version. Like Duke stated it under powered for a 20fter