72 Merc 1150 Need more advise HELP????

[17.5cobra]

Hey everyone


I recently bought a old 115 good compression needed too take the carbs off and clean them but but always seemed to have problems getting on plain never had this problem before with same motor on this boat [Other motor poped a piston]since then I've redone the spark plug leads still no go but it got better.I've played with these cabs lots and gotten alot of really sound advise on tuning them confident they are tuned right.I don't understand this moter sarts right up every time sounds great but just doesn't seem to have that last little bit it needs to be the boat i remember it was.By the way the boat is a 73 17.5 waikiki [Fiberform] looks just like an old Cobra ski boat.

 

[Fuzzytbay]

Re: 72 Merc 1150 doesn't come on plain very easy

Re: 72 Merc 1150 doesn't come on plain very easy

Ok first off, have you done the link and sync procedure?
Second, what is the prop setup?
http://forums.iboats.com/showthread.php?t=168855

 

[Chris1956]

Re: 72 Merc 1150 doesn't come on plain very easy

Re: 72 Merc 1150 doesn't come on plain very easy

On those old motors water injestion is always a concern. First make sure you have spark on all six cylinders. If so, examine the spark plugs If any look real clean, you likely have water injestion.

 

[17.5cobra]

Re: 72 Merc 1150 doesn't come on plain very easy

Re: 72 Merc 1150 doesn't come on plain very easy

The answerers to the first questions is the prop is the same never had this problem before and no too the linc and sync.As to the socond reply yes I have spark on all 6 but 5 and 6 are very clean what to do any ideas ??

 

[Chris1956]

Re: 72 Merc 1150 doesn't come on plain very easy

Re: 72 Merc 1150 doesn't come on plain very easy

If #5 and #6 are clean, you may have water intrusion into them via the crankshaft seals on the lower part of the block. The only way to fix them is to pull the lower unit and the powerhead, loosen some crankcase screws and remove the bolts and lower end cap. The seals are a press fit. try to install three of them, if they will fit.

 

[17.5cobra]

Re: 72 Merc 1150 doesn't come on plain very easy

Re: 72 Merc 1150 doesn't come on plain very easy

Someone told me this problem could be fuel wash from the bottom carb is this posible ?????

 

[OldMercsRule]

Re: 72 Merc 1150 doesn't come on plain very easy

Re: 72 Merc 1150 doesn't come on plain very easy

You asked me to look at this thread, (which I already had), and thought the advice given was spot on and not related or in conflict, (IMHO).

The linc and sync advice is sound, but Chris' advice is also spot on and would get my undivided attention as priority #1.

If plugs #5 and #6 are super clean relative to the others that is a big problem that must be attended to: ASAP. Pull the power head and replace the bottom seal as Chris advises.

There are many related threads on here that talk about the proceedure. I have not done it, (replaced a lower seal), but pulling the powerhead is easy if the engine is not too salty.

If you are moderately handy with mechanical issues I would tackle it. If not get quotes from shops (if you can find people in yer area who know how to work on these old girls).

Having only one remaining functional brain cell n' an attitude ta boot, I would rip right into her!!!

Good luck. JR

 

[17.5cobra]

Re: 72 merc 1150 Need more advise HELP???

Re: 72 merc 1150 Need more advise HELP???

If #5 and #6 are clean, you may have water intrusion into them via the crankshaft seals on the lower part of the block. The only way to fix them is to pull the lower unit and the powerhead, loosen some crankcase screws and remove the bolts and lower end cap. The seals are a press fit. try to install three of them, if they will fit.[/QUOTE

Hey thanks for the advise guys my problem is i'm a little confused on how far the power head has to come apart.My mercury repair manual shows the complete power head being diasembled upon removal is this true or am i missing the smaller picture.I have been wrenching on motors for a long time but this is my first experience wit an outboard.I would like to tackle this problem on my own could anyone give me some advise at on my first move as I don't want to screw this up.

 

[Chris1956]

Re: 72 Merc 1150 Need more advise HELP????

Once you pull the powerhead, there are three or four bolts on the lower crankcase endcap. You need to remove them, and loosen some of the crankcase bolts at the very bottom of the block to allow the end cap to slip out. Replace the rubber oring as well. You also may have brass shims on the endcap. Reuse them.

To pull the powerhead, disconnect the electrical plug, fuel line to the carbs and control cables, drop the lower unit in neutral, remove cowling support and starter. Remove lower u-shaped cowl with the HP decal on it. Now loosen the six or so 9/16" nuts on the powerhead studs. Watch for two in the front under the lower cowling. You need to lift the powerhead straight up 6 inches or so to clear the midsection.