mercury 2str OB 40 HP or 50 HP ? and idle speed problems

Hi all, two questions seeking answers ...

1 ... I have a 48 ft houseboat with 2 mercs out back, both wearing 40 hp covers, however one info plate says 40 ELPTO (S/N OT 694415) 40 hp and the other 50 ELPTO (S/N OT 694454) 50 hp ... I cannot find any reference to either, but need to confirm if I have 2 x 40 hp motors or 1 x 40 hp and 1 x 50 hp ... can anyone advise where I should look ?
ps both motors look identical under the covers.

I need to order waterpump impellers and they are sure to be different if ...

2 ... on both motors the throttle cables are 48 ft long (!) and I have adjusted for throttle response from the Quicksilver duo control, but in doing so the idle speed rises a lot ... how can I reduce idle speed without reducing cabled throttle response ???
Any assistance will be greatly appreciated ...
thanks
rodimer

rodimer said:

Hi all, two questions seeking answers ...

1 ... I have a 48 ft houseboat with 2 mercs out back, both wearing 40 hp covers, however one info plate says 40 ELPTO (S/N OT 694415) 40 hp and the other 50 ELPTO (S/N OT 694454) 50 hp ... I cannot find any reference to either, but need to confirm if I have 2 x 40 hp motors or 1 x 40 hp and 1 x 50 hp ... can anyone advise where I should look ?
ps both motors look identical under the covers.

I need to order waterpump impellers and they are sure to be different if ...


thanks
rodimer

Click to expand...

The information you posted about the difference between the two engines are correct, One is a 40 and the other is a 50. Thank the dealer I'm sure.

Serial number OT694454 is a 2003 MERCURY 50 ELPTO Model number 1050412AD. The PARTS CATALOG part number for this engine from mercury is (803026) - 40/50 Jet 30 (3 Cylinder) 2-Stroke.
The SERVICE MANUAL part number is 90-852572R02 - 40/50/55/60 INCLUDING 30/40 JET.

Serial number OT694415 is a 2003 MERCURY 40 ELPTO Model number 1043412AD. The PARTS CATALOG part number from mercury is also (803026) - 40/50 Jet 30 (3 Cylinder) 2-Stroke.
And it uses the same service manual part number 90-852572R02 - 40/50/55/60 INCLUDING 30/40 JET.

So as far as part go, You can use the same sections for both engines Just remember what engine your working on when looking up certain things, Normally the parts diagram will tell you the differents between the two when needed.

Below is a pretty good resource for you to look up engine part to your engines, But please try to use this as an example only when needed, If your going to order parts over the internet, please consider ordering from this website (Marineengine.com). One reason for a better prices, Also It will help support the website that has helped you and many others in your situation. Thanks.

http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=803026

On the cables, There is a threaded barrel end near the end of the cable under engine cowling, And most likely you should be able to re-adjust the cable barrel end by turning the cable barrel end, That is how you can adjust the cables, This is as long as the cables are not, Stretched out, Bent, or damaged in any way.

Sometimes the cables require a slight preload to help remove the slack in the cable, The service manual will give you a step by step procedure on this adjustment as well if needed.

Hope this helps, Good luck with it.

Hi Boat Tech, thanks heaps for the info, clarifies the situation.

Ref the impellers I was in the meantime at the local Mercury agent, they don't have impellers in stock but gave me the following part number (remember also this is Australia, if that make a difference ... !) ...
Impeller for both P/N ... 8M00245502 or maybe S02. Comes with gasket sets,
P/N 822189 and 822217.

Is this just a difference in location based service or parts manuals ???

Ref the cable, thanks for that. The problem I have is that if I adjust the cable to get better throttle response from the dual helm controls, the idle speed also goes way up ... is there a separate adjstment for the idle speed, so that when I get good throttle response, I can bring the idle speed back to normal ?

Thanks again,
and all the best
rodimer

Hi Bagain Boat Tech,
here is a foto of the impeller housing of the 50 ... hope this helps ...
6776 shows the set and the WRONG gasket
6777 shows the impeller housing .... reuie=res a different gasket shape...
regards
rodimer

After reading this I also need help with a very similar motor. I have a Mercury 40 ELPT S/N OT640143 Model # 1041412AN. Can you please tell me what the parts catalog part number from Mercury is?