mercury 1150 troubles????

[bigb8888]

I just purchased a used boat, with a 77 merc 1150, ran great when i tested it out (for over 2 hours), bought it and today took it out. <br />It ran fine for an hour, then just shut down, I traced the problem to a pinched gas vent hose, fixed it, reprimed and it started right up and ran for a few minutes, and ever since then, it will hit wot at 5200 for about 30 seconds, then fall on its face, will not even plane out, and top rpms are around 3800. I cleaned fuel filter, checked spark on all plugs(good), then even put in new plugs. Still has prolem. It always fires right up, never dies, and if you stop for a while, then try it again, it will hit wot and plane out, but then like 30 seconds to a minute or so, (never the same) it will lose the power again. ????????

 

[Clams Canino]

Re: mercury 1150 troubles????

Look for some other blockage in the fuel system, also have a friend pump the ball while running WOT.<br /><br />Also check the fuel system for vacuum leaks. Remember, the motor sucks the fuel up.<br /><br />-W

 

[69GlassparMan]

Re: mercury 1150 troubles????

Mine did the same think becuase of old gas in tank and gummy carbs. I ran a can of seafoam and it took care of problem. Might try it!

 

[bigb8888]

Re: mercury 1150 troubles????

Hey, thanx for the quick response, However I did forget to mention I did have a friend pump the ball from take off to wot, it made no change in performance, and the ball was hard the whole time. You mentioned vacuum leaks, could anything have gotten damaged when the gas vent line got pinched off while i was running wot, (and then the motor died) because it couldnt get the gas????? thanx again for the help....

 

[bigb8888]

Re: mercury 1150 troubles????

I dont think its from old gas, because the day i checked the boat out, the tank was almost empty, And I put about 12 gallons of new gas in it and ran it almost out, (ran great all day).. then the next day I filled the tank up and it ran about maybe 10 gallons through it before the problem started.. I think I might take it to the lake today and try running a half tank full with some kind of additive to clean carbs. can you use any type of fuel system cleaner additive? also with the engine runnin can you spray gumout out through the carbs to try to clean them out? Or is this bad for a 2-stroke (77merc 1150 I6) Thanks again....

 

[Clams Canino]

Re: mercury 1150 troubles????

Addative = Seafoam. <br /><br />Also external methods to clean the carbs almost always fail.<br /><br />Also try cruising at 4200 for a bit.. see if it's the same issue as WOT?<br /><br />-W

 

[bigb8888]

Re: mercury 1150 troubles????

Thanks for the help guys, I appreciate it. The problem ended up being a gas tank ventilation problem. The vent hose fell off the vent leading out of the boat the other day, and was leaking gas into the back of the boat, so i pushed it back in to the vent hole, needless did i know that someone had put to small of a hose for the vent, and it wouldnt stay in the vent out of the boat, so they siliconed it up in there. so when it fell out and i pushed it back in there, it pushed all the silicone up to the screen, and blocked it off like half way, not allowing the engine to suck the gas it needed for wot. I put the proper size hose on today, and I had a great time on the lake all day... Thanks again for the suggestions.

 

[bigb8888]

Re: mercury 1150 troubles????

Ok, new troubles, not completely sure this wasnt the original problem.. Now the motor (77 merc 1150 I6) is acting real weird. It has a mind of its own. OK the following symptoms are never pinpointed to an exact time frame. (happens when hot or cold.) It sometimes has a ton of power and will hit wot @ 5200 rpm no problem,((Woohooo, the power... its there.... 115 on a 1552 flatbottom)LOL... and sometimes bogging and wot is 4000 rpm, wont hardly plane, and is really struggling, then BAM it kicks in power again, then ughhhhh is loses is again... off on off on.. grrrrrrrrrrr... make up your mind old merc.... Also it barely pees at an idle, (i took the hose off and blew it out, also i covered the 2 exhaust holes mide motor, and blew through the hose and it bubbles under the jet so its not blocked.. it seems to be running hot, the pee is steaming???? and I cant hold my hand to the block for more than a few seconds, OOOOOOOUUUUUCCHHHHH... So i am sure I need a water pump kit. Where can i find a diagram on how to replace it myself. And does the power problem sound like the power pack going out???? Where is the best place to buy merc parts online??? <br />THANKS EVERYONE, <br />BRIAN (Missouri) <br /><br />P.S. I forgot who posted it, but thanks for the post on the trim motor, brush fix.. Brushes where sticking. took a lil emery board and cut it small enough to fit, then removed the brushes and smoothed down the rusty walls and put the brushes back in, and sprayed it all down with electrial cleaner, and my trim works like brand new, no more clicking, wining.. Just straight to the point.... up and down...<br />THANKS AGAIN

 

[gewf631]

Re: mercury 1150 troubles????

Sounds like you've still got a venting problem.<br /><br />Maybe you can buy/borrow a portable tank and see if that helps at all (you can also use that tank for the Seafoam procedure).

 

[bigb8888]

Re: mercury 1150 troubles????

So you dont think its a powerpack/switchbox going bad???? <br />Well as soon as I get the parts and find a diagram for the water pump kit, I will buy a tank and some seafoam and try that... thanks... <br />ALSO I had it out saturday, it ran fine all day, (20 gallons of gas) and then saturday night it started acting up again, sunday it was off on off on off on... for a while it would hit power for a few seconds then bogg for a few seconds, back and forth back and forth, then just bogg the whole time for like a half hour, then ran good for a half hour????

 

[gewf631]

Re: mercury 1150 troubles????

I'm far from being an expert, but my mid 80's 115 had similar symptoms, and it ended-up being my vent (under floor tank, with 2 vents that merged into one, and one was clogged). I also rebuilt the fuel pump - don't know if you've done that, but the parts were under $20, and it only took about 30-minutes. Didn't take care of the problem, but hopefully prevented a future one!

 

[timmathis]

Re: mercury 1150 troubles????

You can get parts at oldmercs.com

 

[Doug Redinger]

Re: mercury 1150 troubles????

I have an old 4 cylinder 35 h.p. from the early sixties that did the same thing. Turned out to be bad check valve gaskets in the fuel pump. Get yourself a fuel pump kit and replace the gaskets and diaghram as they are quite inexpensive.

 

[bigb8888]

Re: mercury 1150 troubles????

Ok, on this (77 merc 1150 I6)so far I have made sure the gas is getting smoothly from the tank to the fuel pump,(it is) also its vented fine, changed the spark plugs, and checked spark on all cylinders (fine), had a friend pump the ball while running out WOT,(no help)I cleaned out the fuel filter and checked the fuel pump diaghrams (they are fine), and operate smoothly they look like new, springs close them fine, and looked at them through a brite lite no holes.... I got a new impeller kit to install cause I'm not gonna run this thing till its peeing like a race horse. Also, I talked to the previous owner which is a outboard mechanic and owns a shop, he did not have seafoam but gave me some sierra fuel stabilizer, and told me to drain the carb bowls, then pump the sierra additive straight into the carbs till it leaks out, and leave it in all day, then drain the carbs and pump out all the additive with the new gas.... then mix the additive with the new gas and take the boat out and run a tankfull through it... says this procedure has given him excellent results. So after i install the new impeller this week, I will do all this and take the boat out this weekend to current river. I will keep ya'll posted on the results...Wish me luck... <br />P.S. I'll make sure to go up river just incase I need to float home..LoL<br />Thanks again for the Help So Far.<br />Brian (Missouri)

 

[2cycle]

Re: mercury 1150 troubles????

Also, check and see if you have an anti-siphon valve at the tank where the fuel line attaches. You may have to take it off and go with a conventional fitting because the extra drag can make you stumble at higher RPMs. My 1500 had the exact same symptoms and this turned out to be my problem as the mechanical fuel pump lacked the umph to suck the fuel through the valve at high RPMs.

 

[bigb8888]

Re: mercury 1150 troubles????

OK... Im gonna lose my mind, I put a new water pump kit in it, It pee's great...((running much cooler))... I also clean the carbs, and bought an auxillary tank, with new gas, and a new pumpball and fule hose and ran it. It again ran great for like 45 minutes, then its loseing power, it jumps from 5000 to 4800 back and forth, back and forth....like every second... or even from 3800 to 4000 back and forth... I checked all the plugs (good spark on all) however I did this at night time.. SHOULD THERE BE LITTLE TINY SPARKS JUMPING ALL OVER THE PLACE ON THE PLUG WIRES FROM THE DISTRIBUTER ALL THE WAY TO THE SPARK PLUGS, ((REAL LITTLE)) AND WHEN I TOUCH THE WIRES, YOU CAN SEE WHERE IM TOUCHING THEM ((MORE SPARKS, GLOWING ALMOST))????? WEIRD...IM CONFUSED...HELP.....?

 

[aidenscott]

Re: mercury 1150 troubles????

you should not see anything at night. You can have a crack in the wires or cap. Spark will find it's shortest way to ground. just a little bit of moisture will cause spark to fall short of your spark plugs. I would change the wires and cap. You could probably tape them to just see if there's a difference. I'm pretty sure that the cap and wires were never changed.

 

[69GlassparMan]

Re: mercury 1150 troubles????

Nothing like Seafoam. I had a motor that had not been run in 20 years. Put seafoam in and idle for an hour then ran on lake. NO CARB PROBLEMS. seafoam is he best.<br /><br />How long did it take to chage inpeller. I have a 1250 but have been nervous to do it as I did not know if it would be a pain

 

[bigb8888]

Re: mercury 1150 troubles????

The water pump kit was an easy install, I do however have a jet, so i dont know how different a prop lower unit would be, but it took all of an hour to drop the jet, replace the parts and slide it back together. (DONT BE NERVOUS) its the first outboard i have owned, it was a breeze, besides they recommend changing the impellar every season, or every other.. good maintenace item there...

 

[bigb8888]

Re: mercury 1150 troubles????

OK, AN AGRRAVATING DAY OF BOATING HERE... I taped all the spark plug wires to see if that helped.. NO LUCK. But i am pretty sure I ruled out the gas problem, I am almost postive its electrical, It ran great for almost 2 hours today, then same thing.. I let it cool down for an hour, and ran fine for 30 minutes, then bam same thing.. almost as if one cylinder quits firing(on, off, on, off, on, off, 1 second on, 1 second off, back and forth..))) but only at higher rpms, 3500 and over.. THIS SUX...