What year is my engine?!

[BrianSmithFishn]

I bought an old 80's bass boat off a buddy for $1200 it has a old mercury 115hp on it. Serial # is B182713. I can not find anywhere what year it is, I even went to two marina's and they couldn't figure it out. I need to find a service manual on it first and foremost. I want to compression test it first so I know what I'm dealing with. However I don't know what is the minimum psi suggested by the manufacture considering I don't even know what year engine it is. This is my first boat I am trying to get it on the water. Planning to replace the water pump, spark plugs, fuel filter, test the thermostat, clean carburetors, already cleaned out the gas tank, change gear oil, and I'm also curious about the prop shaft oil seals and bearing carrier how ever it does not look like others I have seen, so again need a service manual. If you guys could help me out it would be greatly appreciated, thank you so much in advance!

 

[gm280]

:welcome: BrianSmithFishn to iboats. Glad you could join us...

I tried using your posted S/N to locate the year, but with ZERO response. Is that the entire S/N or are there any other numbers on the plate. Also, the owners manual will not have the compression PSI numbers. But most like compression at least in the 100 PSI and higher. But the most important numbers are how close all the cylinders are to each other. The typical percentage is 10%. If your cylinders are reading within 10% of each other is more important them the highest compression number. Can you post a few pictures of the engine with the cowl on and off so we here can see what your are dealing with. A lot of guys on these forums probably can isolate it down once they see the pictures. JMHO

 

[Chris1956]

Looks to be an '87 model. It should have 6 coils and no distributor. It likely doesn't have a thermostat. Carb kits are cheap. Replace float, inlet needle and seat and all gaskets, after a good cleaning.

 

[Fun Times]

Hi, welcome to iboats!

OEM Service manual part number 90-86134--4 covers engines,
75, 80 & 85 (4 Cylinder)(U) 4590512 and Above (A) 8043775 and Above (B) 9139350 and Above (C) 7091098 and Above
AND 90, 115 &140 (In-line 6 Cylinder) (U) 4112635 and Above (A) 8027115 and Above (C) 7047258 and Above
AND 150 (In-line 6 Cylinder)U) 4121435 and Above (A) 8028040 and Above (C) 7048783 and Above....http://www.ebay.com/itm/New-Mercury...ash=item540c8e919a:g:67wAAOSwwPtTwWSO&vxp=mtr

Your serial number is coming up as an,

MERCURY

1987

115 ELPTO

Model Number 1115727

90/115 H.P. (INLINE) http://www.iboats.com/MERCURY-115-6-...iew_id.1702164

 

[BrianSmithFishn]

Wow thank you all! Forums are so great, I love the Internet!

 

[BrianSmithFishn]

Can someone tell me what the compression psi should be? Previous poster said 100, I'm at 70psi on all cyl except #2 which is 60psi

 

[BrianSmithFishn]

Excuse me 80psi on all except cyclinder 2 which is 70psi

 

[Chris1956]

It is unlikely your compression is 80 PSI on 5 cylinders and 70PSI on the last one. It is likely your compression gauge reads low.

However, it really doesn't matter, as the spec is for all the cylinders to be within 15% of each other, and your motor meets that spec.