wcsd106
Petty Officer 2nd Class
- Joined
- Mar 27, 2010
- Messages
- 182
A month or so ago, I rebuilt the carbs and did a link and sync of my 84 Mercury 200HP engine. It is now running well, but I have noticed a slight issue. The engine doesn't seem to get up to the proper rpm level at WOT.
When I take off with the engine trimmed all the way down, my RPMs climb as would be expected. As the boat begins to plane, I have to watch the throttle or I can actually over-rev the engine. Once on plane, as I increase the throttle, I get a good steady climb and increase in speed.
However, WOT rpm is falling short of the normal operating range. i.e. 4800-5200rpm.
It should be noted that I had the hub replaced in this prop last spring and the prop had been repaired the year prior to that after sustaining some damage on the water. The prop is an older mercury 3-blade stainless chopper prop with a pitch of 24. I have the model number of the prop, but I don't have it handy at the moment.
When I set my WOT timing at cranking speed, I did so with the flushing muffs attached to the engine and water flowing. I also set the initial throttle pickup timing the same way. It was suggested in my previous thread that I should have set the initial throttle pickup timing with the lower unit and midsection submerged in water as it would be when the boat is on the water. Would this method apply to setting WOT timing as well?
Any ideas would be suggested. I used to have no problem attaining a GPS speed in the 50-60mph range at WOT prior to having engine troubles. Now my WOT top speed is in the 45-50mph range.
When I take off with the engine trimmed all the way down, my RPMs climb as would be expected. As the boat begins to plane, I have to watch the throttle or I can actually over-rev the engine. Once on plane, as I increase the throttle, I get a good steady climb and increase in speed.
However, WOT rpm is falling short of the normal operating range. i.e. 4800-5200rpm.
It should be noted that I had the hub replaced in this prop last spring and the prop had been repaired the year prior to that after sustaining some damage on the water. The prop is an older mercury 3-blade stainless chopper prop with a pitch of 24. I have the model number of the prop, but I don't have it handy at the moment.
When I set my WOT timing at cranking speed, I did so with the flushing muffs attached to the engine and water flowing. I also set the initial throttle pickup timing the same way. It was suggested in my previous thread that I should have set the initial throttle pickup timing with the lower unit and midsection submerged in water as it would be when the boat is on the water. Would this method apply to setting WOT timing as well?
Any ideas would be suggested. I used to have no problem attaining a GPS speed in the 50-60mph range at WOT prior to having engine troubles. Now my WOT top speed is in the 45-50mph range.
