Question about Merc A, warning to owners

[ryan_4z]

Last night Gary and I were putting some gearfeet on a couple of his Merc. He was telling me that there are spacers inside the driveshaft coupler, because, I guess, the driveshafts are too short. There is one spacer that goes in each end of the coupler, they are about 1/4" thick each. My question is, was this originally designed like this, or was it a quick fix for driveshafts that were cut to short? I also wanted to give all the Merc owners out there a heads up to make sure not to lose these. I understand that if they are not in there that the driveshaft could drop, which could cause some pretty heavy damage to the motor.

[Big Don]

Ryan, you are correct if you don't use the spacers you will damage the engine. It was not designed that way!!!! Some drive shifts were made that were not made to specs.... I believe Sam Hemp found this out the hard way...and then the spacers were made.

[G Stillwill]

I think it was the first kits that had the really short drive shafts the later kits they a little longer. The problem came from the shaft comming down so far it would leave water get past the o ring seal in the crankshaft. Not all of them need the spacers and if used will bind the driveshaft in the gear foot. I measure all of them from the bottom to be sure. Take the gear foot off and push the drive shaft up as far as it will go (it goes in hard as it has to be past the o ring seal in the crank. Put the coupler in without the spacers and take a flat screw driver and put it against the divder pin in the coupler, mark the screw driver where its flush with the bottom of the adapter plate. Take the screw driver and put the end on top of the gear case and see where the mark is in relation to the top of the splines on the drive shaft stub. I leave a 1/8 clearance if its more then that I make two spacers to make up the differance. Two of my motors have no spacers and one has two 1/8 inch spacers.

[ryan_4z]

So, this is the product we are putting on the market? Just think, people are all pissed off because SW hasn't put out a production motor yet. Yet, it is ok to sell a brand new, ready to race motor, that could very likely be scrap if you lose one of these spacers changing your gearfoot. Seems to me some of the members may have their priorities mixed up just a bit. What do you think Eddie?

[ryan_4z]

Don, Does this mean that the spacers were a cheap fix to a problem with the drive shaft being originally cut too short, or was this something that came to light afterwards? The way I understand it is, if you purchase a new Merc from APBA, with the conversion kit, it comes with the spacers, not a properly cut driveshaft. Someone please correct me if I am wrong, as I do not want to scare people away from purchasing one of these motors. From what I have seen, this is the motor to go with in J and AX. I just don't want to see some uninformed individiual take a big loss in something that could be very easily fixed.


Also, I was just wondering, how much does a new Merc J/AX motor, with conversion kit and gearfoot, cost if purchased through APBA?

[G Stillwill]

As I stated this was an issue with the very first kits and not the new ones. I just did two new ones from APBA and neither needed the spacers. Again two of mine have no spacers and the one that has them are for other reasons then for missing the o ring. If you worked on them you would know that when the drive shaft is all the way in its a good 1/2 inch or better past to o ring sealing surface. Cost is 1995.00 plus the cost of the gearcase. Oh and do you really think you are going to scare people away from the Mercs as long as they are running up front in J and AX. APBA had 7 left when I was at Dayton and I know of five of those that were sold since then.

[Fast Jack]

Just took new Merc Apart

Ryan , I just picked up Jacks new Merc at Raliegh, and pulled the power head off . There were no spacers in the drive shaft. If there was a problem with the shaft it seem to have been fixed. I was impressed with the drive shaft and coupler , the quality of the machine work was very good. See ya this weekend. PS, George, I have the powerhead for you. Shawn ( J Dad)

[G Stillwill]

Will see you ar Millville Shawn.

[Team B&H]

There are two different length driveshafts and couplers with and without spacers. If you only have one motor or kit, you will have no issues as the correct coupler is matched to the correct drive shaft. The problem only surfaces if you have several motors and don't always keep the parts segregated. The shorter driveshaft will not go far enough into the crankshaft for the O-ring to seal on the smooth surface past the splines when using a coupler with no spacers. It will run OK the first time you use the motor but when you try to use it the next week, you'll find internal rust mainly on the bottom cylinder. We wrecked a crank and rod and then after we put in new stuff, nearly did it again but took it apart Mon evening after looking inside. It took some detective work to figure it out. The lightbulb came on when I saw two tower housing sitting there without powerheads and measured how far the driveshaft extended up past the exhaust adapter plate.

This is only an issue when you mix up parts, not when dealing with a single enegine or single adapter kit.

[jtower3941]

When buying a new Merc. Do you get any help with this problem?? or is it just a racing engine and you find all this out when its on the bench in parts.

[Big Don]

It is not an issue with the current engines that you get form APBA. Once APBA realized there was an issue they were right on top of it a few year back.

[Fast Jack]

J tower 3941

If you had looked at my post you would have read that a new motor just taken apart did not have any problems. The problem is when people mix and match parts from several motors.. Read Ryans origional post- they were working on more than one motor at the same time