Adjusting Oil Pump for a 100HP Mercury

[agwood75]

I have an 1988 100HP Mercury Outboard that I have recently done some carb work on. When I took the carbs off I had to remove the swivel arm that connects the oil pump to the carb and throttle linkage. When I did this I forgot to mark where the oil pump swivel arm was on the oil pump. I read the SELOC manual and it said to adjust the mark on the arm to the mark on the oil pump, but there are 2 marks on the oil pump where the swivel arm connects. I assume one is for idle and one is for high speed, but I am not sure. Does anyone have an idea of how to correctly adjust the oil pump on this outbard?

 

[sschefer]

Re: Adjusting Oil Pump for a 100HP Mercury

The first mark is normal running the second mark is for break-in. Set it to the first like the manual say's. It's fairly important to make sure you run it on the first mark since running it on the second mark will provide the engine with more oil and could result in a lean condition.

 

[agwood75]

Re: Adjusting Oil Pump for a 100HP Mercury

Sorry for my ignorance on this but by normal running speed do you mean at idle/neutral, or with the throttle forward? I currently have it at the first mark at idle speed or neutral, is that correct?

 

[sschefer]

Re: Adjusting Oil Pump for a 100HP Mercury

Sorry for my ignorance on this but by normal running speed do you mean at idle/neutral, or with the throttle forward? I currently have it at the first mark at idle speed or neutral, is that correct?

If you are following the manual exactly then your question makes no sense. If you're not following the manual exactly you need to start over from step 1. Take a second to read my first post, the word "speed" is nowhere to be found..

Good luck.

 

[agwood75]

Re: Adjusting Oil Pump for a 100HP Mercury

I guess I do not understand what is meant by normal running. Is there a RPM that is designated as normal running, or is idle normal running?

 

[sschefer]

Re: Adjusting Oil Pump for a 100HP Mercury

It has nothing to do with RPM. Normal as in after the engine has run the recommended number of hours to meet the manufacturers recommend break in period. During that period the oil pump is set on the second mark which causes a higher oil/fuel mixture to occur. After the breakin period is over, you are supposed to take it back to where you bought it and have it serviced and one of the things they do is set the oil pump back to the first mark.

If your engine is still on the second mark and you are sure it has more hours on it than required for breakin then you can rest assured that the engine was never taken back to a reputable shop with a certified mechanic for it's post break in servicing. For that matter, it's probably never been properly serviced.

It may also have been damaged if it was run above max breakin RPM's with the oil pump on the second mark because it will result in a lean fuel mixture and could cause piston and cylinder damage.

 

[blazer81.6]

Re: Adjusting Oil Pump for a 100HP Mercury

11 years old.......something to thing about. Disconnect oiler and save yourself some heartache....Blazer