"I have recently replaced my e
"I have recently replaced my engine (Volvo MD2B) with a similar one (MD2). I had been told they were both MD2Bs, however, it has since become obvious that the new one is actually an older engine.
Other than the reduced horsepower, the difference that is causing problems is that the MD2 has a very strong spring in the speed control mechanism, and be strong I mean very very ridiculously strong. The speed control lever on the old engine didn't have a spring and would stay in whatever position you put it in.
I posted on this issue in another forum before I even put the engine in the boat and was told it wouldn't be a problem, but it has turned out to be a very big problem. The spring causes the lever to spring back to idle as soon as you take your hand off the lever. Not only that, the spring is so strong that if you try to push the lever any farther than about half speed, it takes so much force that if feels like something will break.
The two solutions that were suggested were to install a spring that conteracts the one already inside and to get a friction throttle cable (or make your own with clamps).
I tried a few variations on installing a counteracting spring, but it was hard to find a spring strong enough and the result seemed like it was always going to be to cause the lever to spring back to half throttle instead of idle, which seemed like it might actually be dangerous in some docking situations.
I couldn't find a friction throttle cable that would work so I tried the suggestion of using a series of cable clamps to slightly crush the cable. With the cable clamps you can adjust the amount of friction by tightening or loosening them, but it turns out the spring is so strong that the only way to keep it from creeping back is to tighten it so much that it won't move at all, which isn't very helpful.
I also tried adjusting the geometry of the cable ends so that the angles of the cables relative to the levers was better, which seemed to help a little.
Anyway, after trying all of these things the results were far from satisfactory. A lot of force was now required in every throttle position and it would still creep back toward idle. The throttle cable also broke the first time I tried to use the boat, luckily before I left my mooring.
I know there must be a solution to this problem since a lot of boats had MD2s in them. I'm wondering if there is a special type of controls I should be looking for or something. I could switch to a heavier cable, but I would still have the spring back problem and it might just mean something else breaks instead of the cable.
If anyone has a solution, please let me know.
James"
"I have recently replaced my engine (Volvo MD2B) with a similar one (MD2). I had been told they were both MD2Bs, however, it has since become obvious that the new one is actually an older engine.
Other than the reduced horsepower, the difference that is causing problems is that the MD2 has a very strong spring in the speed control mechanism, and be strong I mean very very ridiculously strong. The speed control lever on the old engine didn't have a spring and would stay in whatever position you put it in.
I posted on this issue in another forum before I even put the engine in the boat and was told it wouldn't be a problem, but it has turned out to be a very big problem. The spring causes the lever to spring back to idle as soon as you take your hand off the lever. Not only that, the spring is so strong that if you try to push the lever any farther than about half speed, it takes so much force that if feels like something will break.
The two solutions that were suggested were to install a spring that conteracts the one already inside and to get a friction throttle cable (or make your own with clamps).
I tried a few variations on installing a counteracting spring, but it was hard to find a spring strong enough and the result seemed like it was always going to be to cause the lever to spring back to half throttle instead of idle, which seemed like it might actually be dangerous in some docking situations.
I couldn't find a friction throttle cable that would work so I tried the suggestion of using a series of cable clamps to slightly crush the cable. With the cable clamps you can adjust the amount of friction by tightening or loosening them, but it turns out the spring is so strong that the only way to keep it from creeping back is to tighten it so much that it won't move at all, which isn't very helpful.
I also tried adjusting the geometry of the cable ends so that the angles of the cables relative to the levers was better, which seemed to help a little.
Anyway, after trying all of these things the results were far from satisfactory. A lot of force was now required in every throttle position and it would still creep back toward idle. The throttle cable also broke the first time I tried to use the boat, luckily before I left my mooring.
I know there must be a solution to this problem since a lot of boats had MD2s in them. I'm wondering if there is a special type of controls I should be looking for or something. I could switch to a heavier cable, but I would still have the spring back problem and it might just mean something else breaks instead of the cable.
If anyone has a solution, please let me know.
James"