73 Mercury 40HP

Ffmedic166

Cadet
Joined
Aug 20, 2017
Messages
25
Since my last posting: Ive fitted a 2010ish wiring both controller and engine. Which worked great. Even had the motor in the water a couple of times and did some fishing. WOT top speed from memory was 23mph.

Present Day: I recent had to buy a starter solenoid. I installed the new one and hooked the wires as they were on the old one. The new part had "s"of which I hooked the wire from the key switch which was the same place as old part, and ground "blk" wire to the "I" side. Turned key and it burnt off the "I" lead ground wire. So I contact the seller and asked if it were defective or hooked up wrong he explained from his notes that I had them hooked right and that it most likely was a defective part; so he sent me a new one. I received that one and after cleaning up and fixing the burnt wires installed it, but I didn't put the black wire "I" back on the lead. Turned the key and it fired right up. So a question I have why would that need to be hooked to ground when the body of the solenoid itself is grounded? Any harm or issue not having installed. My main worry is messing up and burning out more wires.

No since the last time it was on the water which was right at a year it ran fairly great. From what I am seeing in videos my motor does not purr and is not as smooth as others. I went out on the water the other day and it fired up with warm up lever and and idled down to ok, not smooth but slight hiccups and jerking of the motor. Since I was at the unloading ramp I reversed and back out and headed to open water. Past the no wake area I opened it up to mid range and it was running good. So I WOT and it increased speed but from sound of motor it increase rpm but not much and the speed was not there. I checked and made sure I was not carrying water (Ripped cover and Florida rains) and it was not much and within few mins my bilge cleared up almost all the water so the weight is was not issue. Previous times on water this thang haul ass. It not being a fiberglass boat and light lets the 40HP rip.

After putting around and fishing not catching anything but a hard time I putted back to the docks, again I opened it up and still not getting the speed or rpm from what I can hear and feel. it not bogging down or shutting down it just feels like the linkage is not going all the way. I got it home and flushed the saltwater and looked at my prop. Maybe a spun prop, but no that is not it though I do need a new lock nut since the lock washer and nut was loose. Even then the splines on the shaft look great. I just replaced the fuel connectors on the engine side and to the fuel tank. I did have a leak before changing them out and was issue of loosing fuel pressure and every so often having to prime bulb. now its consistent with fuel primed fuel line. So that ruled out the fuel issue.

What could be the issue with the motor not achieving the higher rpm band and speed? Also which has to be related why can't I get a smooth idle and run with this motor?

Mixer screw (On carb) is adjusted for tad rich and optimal running. Ive played with the adjustment a couple times out on the water and no change besides stumbling idling to too rich of a idle. So anyone could help me figure this out that would be great.
 

Ffmedic166

Cadet
Joined
Aug 20, 2017
Messages
25
Guess no one know which direction I should look. I thought surely this site had someone who could help.
 

jheron

Petty Officer 1st Class
Joined
Jul 21, 2004
Messages
284
If it sat you may need to clean the carbs and fuel pump?
Pull a drain screw out of the carb and that may give you an indication of if it needs to be cleaned.
Have you checked the compression?
Cheers,
Jon
 

Ffmedic166

Cadet
Joined
Aug 20, 2017
Messages
25
If it sat you may need to clean the carbs and fuel pump?
Pull a drain screw out of the carb and that may give you an indication of if it needs to be cleaned.
Have you checked the compression?
Cheers,
Jon
I went through the carb and put in carb kit about a year ago. I dry store (run the fuel out and drain) so I don’t suspect carbs but I will be taking them off soon to inspect. Compression if I remember correctly we’re about even on both cylinders and above 110 psi.
Going to remove the LU to look at pump since I’ve never had a look at them and while I am at the motor will look at wires to power box and take carbs off. I really don’t want to throw parts at it hoping it fixes the issue.
 
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