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25hp merc xd
I have a cougar cub 10' tunnel with a 25hp merc xd brown stripes dont know what year... and am looking for info on hooking up a tach and water pressure gauge, and where to get a low water pickup, or info on making something that would work...I just ordered a ron hill cleaver prop for the boat where should I start for height? The boat, its just for fun and messing around !! Any help would be great yes I am noob but am very able to do any work myself with some direction
As for setup, when Merc came out with the Cub (or took it over from Evinrude), they also produced a chopper prop for it as well. You were supposed to raise the engine 1" for this prop. It didn't do anything much and I always had better results out of the 18" pitch I had retooled at the prop shop.
Top speed was 45 mph with a 120lb kid, fumes for gas, in the number 5 tilt pin hole and cavitating your butt off to get it on plane. If you go this high with positive trim, be sure to try to plane it off into the wind in as rough of water as you can find to get it going.
Fun boats.
There was a guy in Texas who put Nitrous on his 25 and claimed it ran 80mph!!! I am not sure I would want to be in a Cougar Cub that would go 80mph. That is a little scary.
very cool, but what about a tach hook up and water pressure...or do I not need to worry about the water pressure 1" up from bottom ?
Hi racecar001!
For water pick-up, if you are running a nose cone (or going to), I have seen small pipe used to "build in" a pick-up towards the bottom of the cone (just below the tip of the cone, and direct plumb ithe pipe into the "water flush" hole in the bottom of the leg. Not sure what they used to build the cone though. Either alloy or pannel beaters bog I think. This was certainly neat and did the trick. Also allowes engine to be moved to different hull.
Otherwise, a similar idea to mount a small pick-up on the bottom of the hull at the rear and use some flexible hose (so you can still steer it) and either direct plumb it into the flush hole or "squirt" the water into the water pump pick-up. Not sure how reliable squirting the water in would be though. Direct plumb would be safer.
Haven't done either myself, just seen other examples. Good Luck.
.....sorry, tach hook up!
Easiest and cheapest/lightest, get yourself a "tiny tach". Self powered with one wire to ground and one active wire which simply winds around spark plug lead 3-4 times. Doubles as an hour meter when engine not running. Digital display.
Done this myself and dead easy. Tiny Tach somewhere between $50-$100.
You can find "Tiny Tach" on the web (make sure you get the right model as different one for 2 cyl and 3 cyl 2stroke). Most auto suppliers could get them I reckon as they are pretty common.
how about a normal tach ? I got a gauge set cheap
Thank you guys !!!
PS just got the cleaver prop.. cant wait to try
Check your wiring loom coming from the magneto under the flywheel. "Pulse" wire is usually yellow, you will probably also need red (+) and a neutral (earth) from an outboard "rectifier". I may get this the wrong way around but your motor produces AC current and you need DC. A rectifier will reverse the charge whichever way around it is. Note: You will probably need to fit a 12 V battery to the rectifier and run your tacho from that as your motor will not produce a constant charge. The charge increases and decreases as revs go up and down which stuffs the tacho reading. The needle will suddenly drop off to 0 then back up to revs etc etc. The battery will stop this as the tacho will draw a constant 12 V from it. If you have electric start, wire tacho in from that.
I have had to do all of this and not long ago replaced it with a tiny tach instead. Much easier!!!!! Less weight too.
As for water pressure....too much information for me.
1) I wouldn't be drilling and tapping the head on my engine.
2) If water is coming out of the "tell tale" you have water pressure...enough anyway. If you want to see it, run a small extension hose from your tell tale water outlet to somewhere along the gunnel of your hull in front of you.
3) Get a new impellor for your water pump just to be sure and replace it every 1 to 2 years.
Other than that, I wouldn't be wasting too much time on water pressure. Not a guage atleast.
Spend the extra time on setting up your hull/engine/prop combination. That alone will chew up the days....and nights! Lol!
Good Luck...hope some of this helps.
Whats the deal
I've always wondered whats the deal with the 25XD? Is it just a long shaft version of the xs?
No, the XD is just a fishing motor
Since 1925, about 150 different racing outboards have been made.
Here's a great factory tach for 25XD outboard.
Mercury Part No. 79-859000A1 $72.90
Waterproof... Resetable Hourmeter when engine's not running: Digital tach when engine is running.
about an 8ft long wire for hookup. Just attach the sensor wire to a sparkplug wire per the instructions and the white wire to an engine ground.
I use this on my 25XS racing motor and several other motors.
Tom
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