The picture is of an older 5HP Tecumseh rebuild. It does not have the power I think it should. It does not throw far but part of that is due to the short chute and chute angle of an old Jacobson 526 Imperial Heavy Duty Giant. At about 1/2 of the bucket full it starts to bog down. The governor is kicked in and working but it can't keep up and starts to die if I don't give it some clutch slip to let it catch up. The blades are very heavy and the impeller solid. It's only a single belt system but I think it should be doing much better.
The rebuild seemed to go well but I could not test as there was no snow around at the time. It start agressivly, has a crisp report and seemed to run strong. At the time I did not have a leakdown tester but thought the rebuild went well. It got an hour of run time, three oil changes and sold. The buyer was not so happy with it so I returned his money. I've run it for about an hour testing and it is a weak tosser. I went through the carb and governor and think they are ok - that it's not a lack or gas under load or a governor problem.
This was one of my first rebuids and I think at that time my honing of the bore was lite - not enough. Tonight I went to re-hone the bore and the head bolts were not very tight. On removing the head I found some brown tackie stuff on the head gasket and head rim like in the picture. I think possibly the headbolts were enough to allow decent but not full compression and there is leaking.
So - a few questions:
1. Does the brown stuff in the gasket area look like the result of a leak?
2. For honing I have a stock 3 leg hone used in a drill. The stones are flat. I think engines build up lip in the bore towards the top. If that's right then the hone at the top will have one edge on lip and the other toughing down a ways in the bore missing the mid section - no scoring. Tonight I looked at the bore with a light and it seemed fairly smooth, not glossy and sort of dull or matt. I ran the hone in there for a while and it seemed after looking in that the top got more scroing than below so I figured it may be due to a lip. I went in with 320 and oil by hand to hone below more and it looked better than with just the hone. The piston is still in so tough to get the bottom section. If the lip a problem when honing?
3. Does the brown and black areas on the piston look normal for about 3-4 hours of run time?
4. If properly honed how long should it take for the rings to seat?
5. I've never worked in a shop or took a course so judging honing is a difficult. Any way to judge just how much is enough?
6. I'm almost beginning to think that sticking with medium stones is better than honing with medium then finishind with fine but not positive. Any suggestions?
7. As is, I've rehoned the bore, plan to button it up, torque the heads to spec, and run it under load for an hour to see if it improves. Any suggestions.
8. Could the not so tight head bolts be due to normal loosening? I torqued them on buttoning up the head but never retorqued them after that.
Edit: I should add this engine has a 1 inch crank and heavy so I expected it to have some decent torque.
David
http://www.kedawei.com/snowblower.htm
This message was modified Jan 14, 2009 by trouts2
