100hp questions

[douglas1]

hi,
i just got an older bass boat its a 1990 rajun cajun i have never owned a mercury ourboard before, i cant tell what year it is but the sticker on the right side of the motor bracket has a sn oc147991 . another question is about the engines preformance, i took it out and got up on plane for about 2min then the motor just bogged down to an idle and would not go any faster, the guy i got it from claims the engine only has about 30 hrs on a complete rebuild. i drained about 20 gal of gas out of the boat and it looked pretty nasty kind of amberis in color with a hint of greenish brown when i got the last bit out. i changed the water/fuel seperator filter and the inline fuel filter on the engine. i also noticed that the oil level has not changed at all i have been running it in the driveway with the muffs. but any way i losened the oil bottle cap and noticed the level dropped. should the cap be vented? any input would be helpfull
p.s.
i hooked up a 6gal external tank and ran some hight test in it to try and clean out the motor seems to run fine in the driveway , but i havent taken it back out in the river yet any suggestions would be helpfull

thanks

 

[mr 88]

Re: 100hp questions

You will not use much oil running it in the driveway.Not sure about the cap but if it looks stock then it probably does not need to be vented.The easiest way to clean the carbs short of taking them off is to run Sea Foam through them.NAPA Wally world etc stocks it.Buy a couple cans and initially put in 2-3 times as much as they rec. for 6 gallons and run that. I would also put some in a spray bottle and when its in a higher RPM idle spray that into the carbs, you may stall it.Put it in until its sputtering.If your gas is older than 3-6 months in this day and age you need stabilizer added,which a lot of people add on a tank to tank basis regardless of age.You may also try priming the bulb when its dying out and see if it picks up RPMs. That gas sounded like it was the root of the problem and hopefully the carbs are not so gummed up that they have to be removed.

 

[douglas1]

Re: 100hp questions

thanks iwill try some sea foam

 

[carholme]

Re: 100hp questions

Douglas;

That s/n comes up as:

100 100 4-cyl 0C100000 0C221499 1989 USA

From here:

http://www.marinshopen.se/Motorer/O...rcury2takt4cyl100125hp/tabid/488/Default.aspx

It is a model:

1100412GD MERCURY 1989 100

Parts listing:

http://www.crowleymarine.com/mercury-outboard/359.cfm

Service Manual P/N: 90-13645--2

http://1manual.com/Mercury manuals/Service Manual PDFs/TwoStroke/13645_2/cover.pdf

You must have Adobe Acrobat reader installed to use this manual. If you scroll down to the lower part of the opening page, you will see the various engine components in red. Click on the one you want and when the first page opens, click on the "Save As" icon at the top LH corner of the page and you can save it to your computer.

Gerry