1966 mercruiser 120hp temp sending unit

[57whitehouse]

I had a boat shop working on my old larson for several years during his "spare" time. I got the boat back last month with the enging half wired. I have a repair manual but it doesn't tell me the color of the wire for the temperature sending unit, or the tachometer for that matter. Does anyone have an old Larson with a 120hp that they could look at and tell me the color of the wire that belongs to those 2 items?

 

[alldodge]

Don't have one for a 120 but do have one for the inline 6, and it should be pretty close




And there is also boatinfo
http://boatinfo.no/lib/mercruiser/manuals/mercruiser1.html#/248

 

[57whitehouse]

OOH, thank you sooo much

 

[57whitehouse]

Just an update. I had the boat out on the lake running last week. It's running pretty well for first time out. Still need timing, dwell and carb adjustments.

 

[alldodge]

Just an update. I had the boat out on the lake running last week. It's running pretty well for first time out. Still need timing, dwell and carb adjustments.

Sounds good, and do you know what they should be set at?

 

[57whitehouse]

No, but I have a friend that's a GM mechanic and he knows all that stuff. Plus we will tune it til it runs best.

 

[57whitehouse]

second time out on the lake to adjust timing and dwell, the boat runs like "carp". Can't figure it out. We got the timing and dwell set, but now the engine won't even start. Very little to no spark at all. Took the coil wire off and held it 1/8" from ground and barely saw spark. I think I should see strong spark and hear the snap.

 

[alldodge]

Motor was running good until timing was set ?????

Just to verify
Point gap 0.022 Dwell 31 - 34 degrees
Timing 8 BTDC unless using distributor 112467 then 6 BTDC
Plugs MR43T gap to 0.035
Firing order 1-3-4-2

Valve lash
Int 0.008
Exh 0.010

 

[57whitehouse]

Actually, it had trouble starting and running before dwell and timing was set. The first time out, ran great. Nothing was done before second time out and it ran poorly as soon as I started it. My friend said not to keep the key on while I was doing work on it in the garage, that it could burn the points or the condenser. I did have the key on for a while before he told me that. Maybe on of those are damaged.

 

[alldodge]

In most cases the key ON with points can damage the coil, IF the points are closed.

Check your point dwell angle and spark