Help..I need a plan of attack for my new Merc 1150

Hello everyone,

I just got a boat with a 1973 Mercury 1150 Thunderbolt on it. 115 hp.
I was told, "the engine needs some work." Whatever that means.

I would like some guidance on how to go about checking this thing out and getting it going again. I have never worked on a boat motor before, but have worked with other small engines and am pretty handy so I am looking forward to this challenge. I have the seloc manual for it.

I would love some experienced advice on the steps I should take and in what order. I figure I should replace the water pump, check compression, overhaul the carbs, maybe do the fuel pump. You will see in the pics that the distributor is disconnected. Do I need to get that back on before testing compression? Don't want to burn anything out by doing things in the wrong order.

Can you guys take a look at these pictures and give me some advice on where to start. Sorry for all the pics, but I know it is hard to give any advice without seeing what I'm working with.

Here you can see the distributer is off. The ring to couple it together came with the boat.





THis cable was laying on the bottom of the engine under the distributor. Not sure where it goes. Thought maybe it was a ground for the distributor or something?


Sparkplug wires taped up

Re: Help..I need a plan of attack for my new Merc 1150

Other side.. Wires look a bit rough.




That little tube looking thing on a spring next to the starter looks suspicious.

Re: Help..I need a plan of attack for my new Merc 1150

This plate came with the boat. Looks to go on the engine. Any idea where?



Some shots of the carbs




A pic with the cover on and my future co-captain sitting by.


Any guidance on this project would be very much appreciated.

Thanks,

John.

Re: Help..I need a plan of attack for my new Merc 1150

John, I cannot see any of the pictures, from where I am right now. Perhaps later from home, I will see them.

You can check compression by jumpering the starter solenoid. That will protect the ign components and the distributor. Compression should be 100+PSI and more importantly, even on all cylinders. Since the PO identified the motor "needs" work", I would test compression, install distributor and time it up, and then do a spark test. If both those tests come out OK, then clean the carbs, replace the water pump impeller and the gearoil, and pump some grease into the fittings.
If the ign system, compression and gears are OK, the rest is cheap to fix.

Write back with the results, if you need additional advice.

Re: Help..I need a plan of attack for my new Merc 1150

I think you should get it fixed,because that kid looks mad that he can't go for a ride!.

Re: Help..I need a plan of attack for my new Merc 1150

A few things to know about your motor before you might damage something.

Distributor rotor is NOT removable. It is one piece with the distributor shaft. Replacement is $$$$$

Distributor cap is very expensive ($150, yes 150) so be careful with it.

Coil/plug wires UNSCREW from distributor cap and the coil wire PULLS out of the coil.

As for the photos, I can offer the following...

That tubular piece with the spring is part of the choke linkage.

The flat plate with the screws protruding is part of the throttle/carb linkage. The screws are stops for the various linkages.

You are going to have to replace the plug wires and the internal wiring harness. The wiring on the old Mercs are notorious for falling apart.

Re: Help..I need a plan of attack for my new Merc 1150

John, looking at the pics it looks like the switch box is new and the wires going to it look in pristine condition. That would indicate that perhaps the trigger has been changed as well. All good news for you. The rotor looks new as well. Since the distributor cap was apart and the previous owner said it "needs work" it sounds like he was chasing a spark problem.
The fact that the distributor "adjustment plate" was in the bottom of the boat suggests that the distributor has been removed. Make sure that it was put back in correctly, with number one cyl spark plug wire aligned with the rotor when the #1 cyl is at top dead center.

Re: Help..I need a plan of attack for my new Merc 1150

Hi, that little plate with the 3 set screws is the idle and spark advance and WOT throttle stops. The important thing here is to make sure the spark advance is set at no more than 21 degrees BTDC as the Mercs are otherwise prone to detonation with today's gasolines. There are linc and sync threads on here for the distributor inlines, or Clymer B276 will lead you through it. I have a '74 1500 and had to replace the internal wiring harness and spark plug wires. Also, when you clean or rebuild the carbs, your idle air mixture screws are going to need to be set at least 2 turns out CCW from a lightly seated position to insure that the motor will not bog during the holeshot. I found that 2 1/4 turns is optimal for mine. Great motor, just make sure the cooling and fuel system are always in good shape as these run on the edge..

Re: Help..I need a plan of attack for my new Merc 1150

john,as said check cyl compression first,even though that wont tell ya the overall cond. internally (reed block sealing,cc pressure)it will give ya a baseline to work with.the internal wiring harness should be next in my opinion.they are available aftermarket for around 150.00 or so.great engines,good luck

Re: Help..I need a plan of attack for my new Merc 1150

Outstanding Motor, OUTSTANDING boat!!!

I can take pictures of everything on mine for you so you have them as a reference, my 1500 is almost exactly the same!

The internal engine harness costs $121 shipped from here:

http://www.outboardparts.com/mall/dynamic-results3.asp

I know the distributor is expensive but I've never heard of a distributor "cap" costing that much!!! Buy new plug wires and use the L76V plug that our motors call for..........

Read that manual cover to cover and start plugging........

get a hold of me at :

psholcomb31 (@) msn (dot) com

for both the engine help and Glastron help!!

Re: Help..I need a plan of attack for my new Merc 1150

That black cable you found looks like it goes from the top of the starter motor to the upper cowling ground.........

Re: Help..I need a plan of attack for my new Merc 1150

Thanks everyone. Helps me feel more comfortable knowing there are so many nice people on here willing to give me assistance.
Worked on it a bit this weekend. Took the distributer off, took it apart and cleaned it up. Reinstalled it. The previous owner had mounted it wrong. Bolted it on turned 33 degrees CCW from where it should of been. Now the adjustment plate fits on the distributer nicely.
I'm really optimistic about this engine comming to life. Found it theraputic working on it. Just a matter of finding the time.

Re: Help..I need a plan of attack for my new Merc 1150

Well I got it up and running good. Thanks for all the help and info.
I checked compression. It was good. I replaced the fuel tank, tank hose, internal fuel lines, fuel pumps and rebuilt the carbs. I replaced the distributer with a new used one. Replaced the rectifier that was bad. Replaced the water pump upper and lower housings, impeller, and drive shaft oil seals. Changed out lower unit oil. Re-wired the internal wiring harness. Synced and timed it per Clams Camino's instructions. I also had to hammer out the seized steering piston out of the tilt tube. That was a royal pain.
It fires right up now, runs good, good hole shot and all. Very happy with it. Just need to get a different prop. Only goes up to 4000 RPM. I would also like to check my tach for accuracy too.

My son is very happy about it too. He loves the boat.