Mercury 1150 about to be sent to the dump

[bassboy416]

Mercury 1150.... honestly not sure of the year the serial says it doesn't exist when i look it up the rectifier says 73 on it, but I have always thought it was a 74. I bought this from a guy who said he took it a mechanic every year and was a reliable boat. Ever since I've had it, it has been nothing but problems. PROBLEMS: 1)difficult as hell to start *solution(always have to pump the hell out of the bubble use choke and advance throttle in nuetral for first start) 2) never had any hole shot. It would run great and smoothe but when towing a wakeboarder or going from idle in gear to full throttle would die (had to be eased into full throttle). 3) kept eating batteries (all of the wires from guages to stator) so we replaced all wires, stator, and rectifier.... Once we replaced rectifier, it wouldn't idle. We changed timing so that mark on pulley was 1/2 tooth left of the mark it is supposed to line up with. It ran with better hole shot for 4 hours and then died on the water. Now won't run above half throttle... checked compression today.. .EVERY cylinder was unable to hold pressure meaning that whatever reading I got the pressure would go down to zero very quickly on the guage (checked guage on a dirtbike that was recently rebuilt and guage held at 170psi on the bike). CYLINDER 1= One pull with pull cord and no spark plugs 30 psi and down to zero in less than 1 second) CYLINDERS 2-6 compression in one pull with a pull cord was 60 psi and quickly dropped to zero.... I am trying to decide if I should replace this motor with a new unit, try and fix this myself with no experience, call the whole ($2000 investment) boat a loss and junk it, or try and transfer the chrysler 120 hp 1209hd I have off my tahiti and junk my tahiti. chris 1956 help me! what the hell do I do now?

 

[roscoe]

Problem 1, normal.

Problem 2
WOT rpm?
What prop size?
Linc n sync performed?

Problem 3, eating batteries. What does this mean?
They would go dead while running?
They would not charge?
Or battery would go dead while trying to start motor?
Were stator and rectifier tested before replacing with new?

Messing with the timing is a good way to shorten the life of the engine.

Trying to do a compression test with a rope is likely going to fail.
Try testing it with 3 or 4 revolutions using the starter.
If those numbers are correct, you have serious problems.
Sounds like your compression gauge is also faulty, as it should hold the max pressure reading.

 

[bassboy416]

Roscoe, so for problem 2 WOT RPM has recently dropped under load from about 5500 to 4000 however my tach has never worked right. there were a bunch of bad wires in the cluster that I had to replaced and I believe it may have done permanent damage to the tach. plus before I replaced the rectifier, the tach never worked. Not sure on prop size and no link and sync performed because I've been wakeboarding behind it all year until a month ago and was waiting to do a carb clean and link and sync this winter. Problem 3) bought the boat with a dead battery, replaced with new battery. Battery was not charging properly, it would go out a trip or two and then start having problems turning the flywheel. It would go dead when trying to start but not from over cranking. It would just get weaker and weaker every start until it wouldn't turn the flywheel. The stator and rectifier were not tested. The stator wires were deteriorated to the point they were touching in places under the flywheel and I replaced the rectifier as well because it was inexpensive.

I bought a remote start for the compression test but the wires are significantly smaller than the wires on the solenoid. It will spin the starter but won't engage the bendox. If I use the starter and try it, how do I ground the leads where they stay put? Can I just pull one plug at a time so I only have to ground one at a time? Also, compression tester worked on a dirtbike and held pressure right after I tested the boat. Could there be a bad gasket allowing the pressure to escape? also, why in the world did my number one plug have what looked to be molten aluminum on it?

 

[bassboy416]

Is there a way to inspect the piston without pulling the powerhead?

 

[Grub54891]

Is there a way to inspect the piston without pulling the powerhead?

Yup,use a boroscope

 

[roscoe]

Easiest way to ground out the ignition while doing comp test, is to flip the kill switch to the off position.

 

[bassboy416]

cylinder 1= 30psi but drops to zero after seconds cylinders 2-6 are all within 2 psi of 120psi. took off outer cover near spark plugs today (water jacket?) hoping to see pistons. No luck, all I saw was a lot of rust, a shot gasket, and 3 sheared bolts that were ridiculous to get off.... so whats next?

 

[Chris1956]

Remove the transfer covers on the starboard side of the motor. There are three of them, each covering two cylinders. You can inspect the rings and cylinder bores. Your compression test indicates a clogged top carb or a bad waterpump, causing overheating. Post back....

 

[JimbC]

NM ok

 

[enginepower]

cylinder 1= 30psi but drops to zero after seconds cylinders 2-6 are all within 2 psi of 120psi. took off outer cover near spark plugs today (water jacket?) hoping to see pistons. No luck, all I saw was a lot of rust, a shot gasket, and 3 sheared bolts that were ridiculous to get off.... so whats next?

You have a bad compression gauge. Even if the cylinder max psi is only 30, gauge should hold. Check valve on it needs to be replaced and you can't use one from a tire valve stem as the spring would be too stiff.

 

[bassboy416]

I bought a mercruiser 5.0 i/o and am either going to sell this motor for parts or try to do a full overhaul... please feel free to contact me with help and or for parts or the motor... will have lots of components cheap... 2 starters... one is 4 months old... new battery... new stator and rectifier... 5 working pistons with 120-125 psi in cylinders 2-6... new spark plugs... working fuel pump, flywheel, ignition,wiring harness, solenoid, lower unit (no leaks), water pump housing, prop, and others....

 

[inthedirtagain]

What prop is on it, and what do you want for it? Pic?