There was an excellent post made on June 26, 2000 dealing with distrutor shaft seal leaks in the 700 series with B230 engines (cam driven distributor on rear of head). The distributor o-rings are available from Volvo, but the shaft seal is not. A few weeks ago I even looked in the parts manual, and the shaft seal is not shown. Jim found that Honda part #91205-KF0-003 is a replacement for this seal. It works perfect. However, it is not stocked by many Honda mower dealers, and some want a $7.50 service fee to order a non-stocked part. The seal is about $2.50 US from Honda. This seal is simply a metric seal, 12mm X 20mm X 5mm. It is for a 12mm shaft, it is 20mm OD, and 5mm thick. It is also a rubber coated (thats good) seal with two lips. As near as I can tell, the original seal Volvo used came both rubber coated and non-coated, and appears to be a single lip seal although I can't tell for sure. Now for the substitutions. Chicago Rawhide seal 4701 is exactly the same with a single lip. Transcom seal #12X20X4TC is a double lip seal, rubber coated, that is 4mm thick. That is what is in the distributor in my wife's 745T. When I installed the seal, I set it with the outer edge flush with the distributor housing. There is a 1mm gap behind it which won't hurt anything. You could also set it all the way back in the housing, and it should also be fine. It fits tight, and I doubt that it would ever move out against the seal retainer. The Transcom seal cost $1.82 US from a local bearing sales house. For those of you who can't get those brands of seals, simply contact a bearing supply company and tell them you want a 12mm X 20 mm X 5mm seal, preferably rubber coated with double lips.