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View Full Version : How to set up a new J/A Mercury



smiley
12-19-2009, 07:40 AM
Hi, I am returning to racing, this time with six grandkids. The equipment is certainly different in the A/B classes.

I Just took delivery of a new Mercury J/A motor with the new conversion equipment on it and a George Stillwill blueprint job.

Do most of the racers use the kill switch on the motor or do they connect remote switches installed near the crash throttle?

Who is the contact(s) and person(s) who blueprints and shapes the racing gearbox foot? What is the fair price for this service?

Does the APBA sell the AX restrictor plates? The J restrictor is installed now.

Is there an attached thrust bracket assembly similar to the OMCs available for the Mercury? Is this supplied by Brown Machine?

What is a good trim starting point for tuck angle on an Austin copy runabout?

From your experience, how long does it take for a new motor to finally seal the rings and come to full power?

Thanks for your help to these questions and any other advice you can give to a returning newby.

Smiley

Skoontz
12-19-2009, 08:15 AM
Smiley:

Have fun racing with the kids! We did not use the side kill switch, I saw no real purpose for it so the wires are just loose in the bottom of the cowling.
APBA rules say you must have a kill switch approved that connects to the driver in case they are thrown the motor dies. So, we use the Mercury kill switch and located it under the hand throttle a little forward on the left wall of the cockpit with a teather.

You can buy templates from Brown tool manufacturing out in Jersey, there is no real need to farm out BPing a gear case shape when Ace hardware sells files and polishing cloth. Brown has an add in "the propeller" magazine.

The Merc motor does not require a restrictor in AX class. The plate you have on is for J.

The thrust bracket is a Brown Tool part, usually about $50, but you will also need to get the snubber they make for the Merc motor, which attaches to the front of the gearcase/tower and thats another $50.00.

Don't know them runabouts, but I'm betting if you started with the motor flat, then document everything else, that should get you where you need to go.

Your starting with kids, so the goal ias to get them on plane first, then play with the set up.

George will tell you that by the time you get through 2 gallons of fuel, that motor should be broken in. Ours seems even better after a full season, so, I dunno about that.....

Good luck and have fun!

AZOutlaw
12-19-2009, 08:18 AM
Contact the J class reps in your area's local clubs...here is a link to Seattle Outboard Associations (SOA) web site http://www.seattleoutboard.org/

and latest newsletter with "your local" J class Racer contact info. http://www.seattleoutboard.org/PP/11.09.pdf

Glad to hear another racer is returning with kids involved. SOA has a great J program going on with elims needed on most weekends. They have great support for the kids from all racers in the region.

AZ Outlaw
APBA Council at Large Member

smiley
12-19-2009, 10:27 PM
Thanks Bil and AZ.

I forgot there is only one restrictor plate for the Mercury.

Others have told me that these Mercurys are pretty tough motors and have a long service life and good materials in the moving parts. That is good news. Sounds like a good chocie for a motor for new racers. Also the new electronic ignition systems has simplified the operations as well. This will be fun.

Now to get accustomed to the new laws by the state and local autorities regards to noise, speed limits, traffic flows, boater's education cards, etc.

Smiley

Skoontz
12-20-2009, 04:14 PM
Smiley:

If you want to test omn more lakes, just get a 4 stroke conversion kit and paste it to each side of the engine hood. If anyone asks about oil in the gas, tell them it is oxygenators to lower emmssions, they will never know the difference.

Also, for speed limits, get a GPS to stick right at the legal speed limit of a lake, we have omne that has a 35MPH limit and we have a GPS stuck at 36 and change. Every time the game warden stops us, we just show that GPS and lifes good.

smiley
12-20-2009, 06:40 PM
Bill, you are so deceptively cunning, chuckle chuckle. It may work for you but my wife says I am the most unlucky auto driver. I drive the speed limit and always wear my seat belt. The first time I go over the limit I get caught. The first time I pulled out onto the highway without a seatbelt, I got caught. We are currently thinking the best solution is to use the old KG7 with the fishing lower units for initial runs on a lake and for the first runs with the kids. The local enforcement agents, whoever they are will come by, see the underwater exhausts which qwells that issue, they go about 38 mph which is good for initial familiarization of the boats and J speeds and also does not require the state boaters education card because they are less than 15 HP. That takes care of the other issues. If the local neighbors call in the "speeders" we will calm those officials with this equipment and then subequent reports later on may not receive the same enforcement attention because they will know us and calm down to local residents. Then we can switch to the OMCs and Mercury. That is the hopeful plan.

Smiley

Skoontz
12-20-2009, 07:35 PM
Bill, you are so deceptively cunning, chuckle chuckle. It may work for you but my wife says I am the most unlucky auto driver. I drive the speed limit and always wear my seat belt. The first time I go over the limit I get caught. The first time I pulled out onto the highway without a seatbelt, I got caught. We are currently thinking the best solution is to use the old KG7 with the fishing lower units for initial runs on a lake and for the first runs with the kids. The local enforcement agents, whoever they are will come by, see the underwater exhausts which qwells that issue, they go about 38 mph which is good for initial familiarization of the boats and J speeds and also does not require the state boaters education card because they are less than 15 HP. That takes care of the other issues. If the local neighbors call in the "speeders" we will calm those officials with this equipment and then subequent reports later on may not receive the same enforcement attention because they will know us and calm down to local residents. Then we can switch to the OMCs and Mercury. That is the hopeful plan.

Smiley

Why not just run the Merc 15 with stock lower units? We do it with OMCs....

smiley
01-01-2010, 01:53 PM
Bill Says,
"Why not just run the Merc 15 with stock lower units? We do it with OMCs...."

That would work except I do not have stock lower units. I do have two complete KG7s with stock lower units that will work fine. I did have to add another bowden wire on the throttles because the old motors are push vs pull for throttle controls as well as transo jacks. No problem. We are now set to run the rigs. Must wait for better weather and temps.


Smiley

smiley
01-17-2010, 10:44 AM
Well we got two of the grandkids out on the water Jan 9. The weather cooperated and didn't pour on us at Kitsap Lake, Bremerton, WA. We used the runabout with a KG7 standard lower unit. I did three test runs. First too low, kicked in. 2nd to high to far out. third run kicked in a little and dropped 1/4 inch and saw 37 mph with a two blade 7 3/8 x ? (possibly 11 in) bushed down OJ prop. The boat still didn't settle down but was approaching a smooth run. It seems that the motor may have been loaded up a little too much. Compression test on the motor is 90 and 95 three days afater runing the motor. I cannot remember what normal compression should be for the KG7.

My old KG4 standard did 38.5mph on a calkins runabout in the 60s'. Sis raced it and was undefeated against the other KG4s and Kg7s at 38.5 mph. That is the only comparison I have. So 37 may be ok. That old KG4 was exceptional. I sold it to Mark Demaray who dominated the Region 10 with that motor and made some records.

Any help would be appreciated.

Question.

What is a good fixed vertical transom height to run both the omc and merc15 motors on the same boat?

The two boys 16, 17 had a great time and learned that this can be a real great thrill.

The motor didn't peform as well as I would like. I may have a poor coil or capacitor on the bottom cylinder. The top spark plug had the customary chocolate brown color on the porcelain tip. The lower plug was snow white. I wrapped a wire around the lower spark plug wire for the tachometer sensor pickup. That may have affected the spark? When we ran the motor it sometimes ran on one plug and we had to nurse it around the lake a while before it would kick in on two cylinders.???? We need to get out again and try again. Try a couple other props and see.

Smiley

Mark75H
01-17-2010, 11:09 AM
A white spark plug generally means too lean, which would be very uncommon on the bottom cylinder of a Merc twin. I doubt that you have been running on one cylinder the whole time.

37 sounds like a good speed to start getting seat time, but the feel of the boat will be completely different with the racing lower units and props.

Regular J only goes up to 16, but the 17 year old can race in AXS

smiley
01-17-2010, 07:25 PM
Sam,

You stated, "A white spark plug generally means too lean, which would be very uncommon on the bottom cylinder of a Merc twin." I AGREE WITH YOU 100% AND THAT IS WHY I AM PUZZELED ALSO. I checked the timing and the points are set 180 degrees apart!!! I think I will swap plugs and see what happens.

There is much to teach since none of them have ever seen a boat race. With six a good pit routine is a must so we will rehearse that scenario to become comfortable and efficient with the process.

Bob

smiley
02-10-2010, 03:42 PM
Possible problem with the lean running condition of the lower cylinder may be a bad lower seal thus less fuel draw and a lean running condition. The motor did not have what I would call full strong torque at the slower speeds and did run on two cylinders but with low power and you had to nurse the motor to get the top speed. Thus one cylinder was probably normally calibarated the other very lean and little power output.

No telling how long the motor had been dry and the seal may be shot. Need to replace it.

Smiley

smiley
05-31-2010, 06:56 AM
Much progress has been made. Two of the six kids said they will race at Silver Lake, Everett, Wa this weekend. June 5. One in J the other in AXH with an OMC. The other four are not as far along in the training due to school and other conflicts. Once school is out we plan to "practice two times per week. Hopefully by mid season they will all be on the water.

Last weekend I reaced AXH with the new Stillwill blueprinted Merc at Newport, OR on the Willamette River. Interesting experience. As you said after two gallons of fuel I put this motor on the hydro with recommended prop and 1/8 inch tuck and 1 1/2 inch depth and first heat the gps pegged 51.1 on a river. Take 2-3 mph away and you get 49 .1/48.1 mph for the first test. Not too shabby for the first time. Should get more speed with less tuck and min height setting. Of course I still can't corner for beans but it is fun to pass some boats on the straights. George told me to run four gallons of fuel through it before I plug the thermostat. I assume this is to provide a good breakin and seal before adding heat to the formula.

What speed increase can one expect in ASH for plugging the thermostat on the port side? What is the theory behind that modification? What speed increase does 1/8th in height difference makes?

This sport is a kick in the pants.

Smiley