emmurphy50
Seaman Apprentice
- Joined
- Jul 29, 2014
- Messages
- 40
Hi all...
I have a 81 Wellcraft 196 Sunhatch with a Merc 470, purchased mid-July, pre-Alpha outdrive. It was having the miss issue/bogging down at high RPMs that others seem to have. I did a full tune-up on it including wires, points, condenser, coil, cap, rotor - set timing to 4-5 BDC and dwell was at 29.5 - within range and should wear through the spec. All Merc parts except NGK plugs. I also replaced the thermostat as the engine was running fairly cold (135-140 vs. 160) and fuel economy was admittedly poor from the past owner.
One thing the boat did well is shift very easily and smoothly. Other Merc owners in my family commented how smooth it was.
When I replaced the coil I noticed it was very far forward in the band clamp holding the coil. When I replaced it I centered it in the clamp, having it more aft.
I got out on the water, and at about 65% forward throttle the throttle was sticking, jammed at one point, and used some "elbow grease" to have to free it loose - fearing it was stuck open while underway. Should have just turned off the key in hind sight.
Working it loose, and it having less resistance afterwords, I boated for an hour and when we stopped to let the kids swim, I pulled the cover and saw the throttle linkages were hitting the coil because I did not have it sitting forward in the clamp as before (which looked odd to me when I did the job). My throttle cable runs on the starboard side of the engine and when the cable pulls open to stern, the linkages open in an arc from starboard to port - where it got stuck under the coil which I mounted too far aft.
Since that time the shift is very hard, and late - with RPMs increasing before the shift to about 1000+, the RPMs also go up before I hit the forward idle stop on my throttle handle, which it did not do before.
Also, I had my boat unusually stall while coming into the dock - I suspect the shift engine kill switch was the cause.
I'm guessing I need to do a full shift cable adjustment - is there anything I also need to do with the throttle cable? That is what I probably put the most force or stretch on. Additionally, my shift cables are well behind the engine - any tricks to working on them in the only really confined engine space in my boat?
Finally, while I have you all - the boat ran far better - it got to WOT RPMs (4200) now at 2/3 open throttle (still with a very light miss) with a fairly full boat and 1/3 a tank of gas. Previous to the tune up (or cable misadjustment) I was doing WOT at full throttle. I am not sure if it was the tune-up/stat or cables moving that caused the change.
Any other ideas on the miss - much better but not gone. Other thing I can offer is my tach sticks and needs a number of taps to read - and then will stick again. Read elsewhere this possibly being a contributing problem.
Thanks all...
I have a 81 Wellcraft 196 Sunhatch with a Merc 470, purchased mid-July, pre-Alpha outdrive. It was having the miss issue/bogging down at high RPMs that others seem to have. I did a full tune-up on it including wires, points, condenser, coil, cap, rotor - set timing to 4-5 BDC and dwell was at 29.5 - within range and should wear through the spec. All Merc parts except NGK plugs. I also replaced the thermostat as the engine was running fairly cold (135-140 vs. 160) and fuel economy was admittedly poor from the past owner.
One thing the boat did well is shift very easily and smoothly. Other Merc owners in my family commented how smooth it was.
When I replaced the coil I noticed it was very far forward in the band clamp holding the coil. When I replaced it I centered it in the clamp, having it more aft.
I got out on the water, and at about 65% forward throttle the throttle was sticking, jammed at one point, and used some "elbow grease" to have to free it loose - fearing it was stuck open while underway. Should have just turned off the key in hind sight.
Working it loose, and it having less resistance afterwords, I boated for an hour and when we stopped to let the kids swim, I pulled the cover and saw the throttle linkages were hitting the coil because I did not have it sitting forward in the clamp as before (which looked odd to me when I did the job). My throttle cable runs on the starboard side of the engine and when the cable pulls open to stern, the linkages open in an arc from starboard to port - where it got stuck under the coil which I mounted too far aft.
Since that time the shift is very hard, and late - with RPMs increasing before the shift to about 1000+, the RPMs also go up before I hit the forward idle stop on my throttle handle, which it did not do before.
Also, I had my boat unusually stall while coming into the dock - I suspect the shift engine kill switch was the cause.
I'm guessing I need to do a full shift cable adjustment - is there anything I also need to do with the throttle cable? That is what I probably put the most force or stretch on. Additionally, my shift cables are well behind the engine - any tricks to working on them in the only really confined engine space in my boat?
Finally, while I have you all - the boat ran far better - it got to WOT RPMs (4200) now at 2/3 open throttle (still with a very light miss) with a fairly full boat and 1/3 a tank of gas. Previous to the tune up (or cable misadjustment) I was doing WOT at full throttle. I am not sure if it was the tune-up/stat or cables moving that caused the change.
Any other ideas on the miss - much better but not gone. Other thing I can offer is my tach sticks and needs a number of taps to read - and then will stick again. Read elsewhere this possibly being a contributing problem.
Thanks all...
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