What parts are available for the old 25ss merc

[KG4]

Have an old 25ss powerhead that popped a long time ago.Been in my garage for better than 20 years and was thinking about getting it running.I think the crank is shot.Just wondering if their are any parts for this engine.Thanks

[jeff55v]

25ss

I dunno for sure, but isn't that just a 22ci merc service powerhead? I would think any of the old 22ci parts would fix her right up. The important thing is a good tower and lower unit.
(BTW, there's a 25ss on eBay
http://cgi.ebay.com/ebaymotors/Mercu...mZ140314248157

[KG4]

Jeff,Will the old powerhead bolt up to the current 25xs tower or is the bolt pattern different?

[Guest]

25ss

I have both models of the 25SS and both models of the 25XS,. I appears that the issue will be the drive shaft length and the spline. The 25SS had the standard 6 spline standard length drive shaft. The early 25XS had the same basic tower as the 25SS while the later 25XS had the short tower common to the 44XS. Also the later shaft had 8 splines I beleive. I will go into my where used data and try to get part numbers. You can look here at the engines.
http://www.hydroracer.net/forums/sho...t=8549&page=15
Alan

[laddies]

No the 2 types of engines are not interchangealble. The power head that will work the easiest is 1973 to 77 as it's the same ign. system but with a complete swap with the complete power head with the ign sytem anything to 81. the earlier sngines were different ign stysems.

[swheeler]

I'm sure you could find parts, both new and used. I comes down to what are you going to do with the powerhead, built a race engine? If it were my powerhead I would tear it down first and see what parts you are going to need. Worst case, these engines and powerheads appear on ebay from time to time.

[ZUL8TR]

Mid 1970's 25ss parts

Have an old 25ss powerhead that popped a long time ago.Been in my garage for better than 20 years and was thinking about getting it running.I think the crank is shot.Just wondering if their are any parts for this engine.Thanks

East coast Marine has some parts that might be usefull. If not listed give them a call. Here is a link to their site and the 1974 to 1976 25ss engine

http://www.eastcoastmarineservice.co...76Merc25SS.htm

[sbowman]

25SS parts

Have an old 25ss powerhead that popped a long time ago.Been in my garage for better than 20 years and was thinking about getting it running.I think the crank is shot.Just wondering if their are any parts for this engine.Thanks

I have lots of parts for the 25SS motor. Take it apart and let me know what you need. Shanon email- tracalbi@juno.com

[3autility]

Merc 25SS

What spark plugs do you use in this motor? I have used Champion L61-Y and have seen L78-V also listed. What NGK plugs match up?
Thanks

[ZUL8TR]

1970s 25ss spark plugs

What spark plugs do you use in this motor? I have used Champion L61-Y and have seen L78-V also listed. What NGK plugs match up?
Thanks

I still have my 1973 25ss and use the Champ L 61Y the coldest Y gap in that gap series with 14 mm 1/2" reach. The L78V is a surface gap plug that came standard on my engine. When I was racing this engine it was determined that the V series plug being a very cold design was prone to fouling and also was impossible to read for fuel mixture control. Better performance was obtained with the L 61Y with its deep reach spark. Here is a link that cross references the Champion to NGK plugs. You will find X refs for the L61Y and the L78V among others.

http://www.spark-plugs.co.uk/pages/t...on860-n288.htm

BTW I also experimented on the L61Y indexing and increased gap for better fuel flame advance and combustion that increased engine rpms therefore was able to reduce the static timing somewhat and compensate the power with the increased plug gap thus reducing the effect of excessive piston crown heating that excessive static timing would create.

[STEVE FRENCH]

powerhead on e-bay to watch

http://cgi.ebay.com/ebaymotors/1976-...1%7C240%3A1318
.
.

[dndsam]

I am new to the Hydroracer community and have been searching for information on the Merc 25ss. I am a bit confused on which spark plugs should go in this motor. I understand the motor was designed for a perma-gap plug(L78V), however I have two different kinds that came with my motor and I am not sure what to use. I have a box of L3G plugs and information I have found show this preceeded the L78V's. The ones in the motor have the gap adjustment cut off so just the tip is exposed. Any reasoning for this? Should I use these plugs and if so, should I cut the adjustment tip off or leave it on and gap it. I also have the L-61Y plugs available. Please shed any guidance on what to use and what gap these plugs should be set at if used over the perma-gaps. Is there any information or literature available on this motor? Thanks in advance for any help.

[ZUL8TR]

25ss specs and other

I am new to the Hydroracer community and have been searching for information on the Merc 25ss. I am a bit confused on which spark plugs should go in this motor. I understand the motor was designed for a perma-gap plug(L78V), however I have two different kinds that came with my motor and I am not sure what to use. I have a box of L3G plugs and information I have found show this preceeded the L78V's. The ones in the motor have the gap adjustment cut off so just the tip is exposed. Any reasoning for this? Should I use these plugs and if so, should I cut the adjustment tip off or leave it on and gap it. I also have the L-61Y plugs available. Please shed any guidance on what to use and what gap these plugs should be set at if used over the perma-gaps. Is there any information or literature available on this motor? Thanks in advance for any help.

------------------------------

I have a 73 25ss that I raced in 25ssh from 73 to 80. I used the L78V at forst then switched to the L61Y projecting tip set at 0.045". Get rid of thje plugs with the electrode clipped off. If you need new plugs the L78V is still available in Champion or NGK, the L61Y is no longer avail in Champion but is available in NGK. See my post above for a link to a Champ - NGK conversion.

The 25ss came with NO users manual but just a single sheet of specs. Here they are

displacement = 21.9 ci
max recommended rpm = 6600
oil ratio = 25:1
crankshaft end play = 0.003" - 0.010"
mag timing = 38 degrees BTDC
gear ratio lower unit 16:21, 15:15 available
carburetor = Tillotson KC16A fixed jet 0.061" sea level to 1000 ft
sparkies = L78V

Racing exerience settings

max rpm = 7000 -7100 prop and engine height dependent
carb jet = 0.061" worked for me in Florida all season
sparkies = Champ L61Y
Mag setting = 40 degrees
Crankshaft end play = 0.008"

The 25ss has a CD ignition that is very sensitive to good grounds and clean wires and connections. The grounds are at the 2 coils. Pull the coil switch box plate off the engine and pull the coils off. Then take the rubber covers off each coil and note there is a ground from the terminal to the coil ceramic and it is tapped. Replace this ground and retape with duct tape. If you can get them use the later coils use a flat steel plate from the terminal to the ceramic also tapped. There is also a ground from the lower coil to the engine block, replace it as well. The remaining ground is from one coil to the other replace it if needed.

Clean all insulation on the wires and check all connections. You need to pull the flywheel to complete this. Get a flywheel puller at Pep Boys or?

To set the timing you need a inductive timing light that is powered by 12V. You also need to degree the flywheel relative to the TDC mark on the flywheel rim. I have marks for 36, 38, 40 and 42 set on the flywheel. I used the top cylindere for the timing marks, You could use the bottom cylindere if desired since there are TDC marks on the flywheel for each cylindere. You also need to place a stationary mark on the engine that lines up to TDC on the flywheel to use as a timing reference.

You need to go inside the engine to set the end play and set the reeds. The engine came from Mercury with 0.010" reeds and short stops. The APBA stock inspection manual recommended that these be replaced by the stock 1973Merc 200 0.012" reeds (34-56704A1) and the Merc 200 longer reed stops (34-64632). The reed height is set at 3/16" +/- 1/32". But be sure that the crank counter weights do not hit the reed stops with the crank in its max upper or lower position. This can be controlled with the end play setting.

To set end play you need a shim kit that is used at the top bearing cap. The end play setting it measured with a feeler gage at the top bearing cap by pushing down on the crank shaft to bottom it out on the lower crank bearing riding surface and placing the feeler gage between the top bearing and the bearing riding surface on the crank. You can also check to see that the crank shaft is centered between each cylindere centerline.

Engine crank seals at the top and bottom should be replaced if you can get the correct ones. Contact me if you want specifics here. Also check the bearings on the crank. Seal the crank case with aenerobic sealer available from Permatex, Locktite and others.

There are other items that need to done like the lower unit but this is a start for now.

[beshears]

I have a complete 25ss for sell, it's in very good condition. Email me d.beshears@comcast.net for pics & pricing.

[dndsam]

Thank you for the informative information on the 25ss. I am really intrigued with this motor and it sounds like I have some work to do on mine to get it up to speed, but am up for the challenge. Any additional thoughts are always welcomed as I am a newbie to this forum and engine class.