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Rebuilt 1995 90hp Mariner won't plane off

J

JeffJJackson

New member
Hi all, I'm Jeff
3 cylinder 2 stroke*
This is my first boat and when I got it it ran perfect for 3 months. Then it started stalling. Here is a list of all that's been done to it over the past 1 and half:
work done:
-piston bored because of knocking(the guy says rebuild, but i don't think total rebuild)
-fuel pump
-carbs
-changed props
-plugs (compression is great)
-flywheel*
-changed power pack (current pack comes off a 6cylinder that had two packs like my one so I assumed that one of them could be used on my motor) is this a problem? It's my next move in my long list of problem eleminations.
problem:
-boat won't plane( even with a person standing at front)
- rpms get up to about 4k full throttle (still no plane)
I've learned everything I know about boats by working on this boat and reading its manual and from the mechanic that's been helping me out. *I'm totally lost now because my mechanic seems totally lost. *Frustrating!! Please!! Help!! Lol!! Thanks in advance for any advice guys. God Bless.
One last thing, could the motor be too low.. While at a shop for a while, someone stole the adjusted screw (lever) that was on the hi-jacker. It's at the bottom right now and my mechanic says that could be a problem because what's the point of having a hi-jacker if you're gonna have it at the bottom, it's not jacking the motor up. Thanks again.
 
I'd be looking at the prop you changed. If you still have the old one try putting it on again. If it's idling and running up through the revs alright but not revving out the prop would be a good place to start. There are some very informative recent threads on selecting props.
 
Oil
wynjim55 said:
I'd be looking at the prop you changed. If you still have the old one try putting it on again. If it's idling and running up through the revs alright but not revving out the prop would be a good place to start. There are some very informative recent threads on selecting props.
Click to expand...

The original prop was a 22 and I changed it to a 19.. The boat did the exact same thing.. The inside of the prop showed no signs of wear or anything that would suggest it was slipping. Do you think the 6 cylinder power pack could have something to do with this problem.
 
Check for proper spark on all 3 cylinders, must jump a gap of 7/16" or more.--------You can also check for proper firng of each cylinder, put your own timing marks on the flywheel if you must.
 
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I'm not sure but I'm almost positive the timing is right and its firing on all plugs but I'm definitely gonna check them again to make sure. The motor idles and runs very smooth and quiet though, could there be a lower end problem that would cause this?
 
Post # 1 you ask about the used powerpack.--Then in post # 7 you say that you are ---" not sure but I'm almost positive the timing is right and firing on all cylinders " -------?????
 
Ok, I see what you're saying. I "assumed" that the timing and firing are ok because the motor is cranking and running very smoothly. In my head, when i think of a motor having a misfire problem, i thought it would run choppy and sound out of sync.. The reason i asked about the power pack is because, "in my head", the motor seems like something is just not letting it rev out like it should..and im thinking the power pack is not sending the right "rev" message to it because its suppose to be sending a "rev" message to a motor with 6 cylinders and not 3 cylinders, like mine. Am I thinking wrongly on what the power pack actually does and how it actually works? I think of it as a computer that lets your motor know when to "shift" and open up into the next level of power, almost like shifting.
 
You are totally wrong on how a powerpack works.----It is not a " computer " by any means.-------Simple testing is how you come up with answers.----------Perhaps when you run at full throttle out on the water you can look into the throttle bores ( strong flashlight ) and see if the same amount of fuel is coming up the main jet.
 
Could ethonal gas or debris in my fuel delivery clog up the jets? Im asking because the guy i worked for said they have recently gotten alot of boats in with the exact same problem and its the gas causing problems in the lines. He suggested that I get the jets blown out and get a better water seperator. How does that sound to you?
 
I do simple trouble shooting and testing to come up with answers.----------------Worked on a 50 HP Mercury this summer, dealer had installed new powerpack and stator to solve a lack of power problem.--------Using experience and observation it was discovered that the main problem was exhaust tuner 66% plugged with carbon.
 
I'm starting to understand now, more than ever, that a very large part of working on motors, not just marine engines, is trial and elimination. There are so many factors and situations that can give you the exact same symptoms, that you just gotta get into the motor and test and eliminate possibilities until you've found your problem. I'm no mechanic, as I'm sure you can tell by my posts, but I'm not gonna let this dang engine beat me. I'm gonna try everything you guys have been telling me and keep at it until this things has me fishing in crappie tournaments.
 
Motor dies when I decelerate.

Hey guys, thanks for all the help. I'm up and running. Now I have another problem. When I've been out running a while, my ball goes soft and motor dies when I decelerate. If I'm sitting still and try to crank back up, it doesn't want to. Any suggestions? Thanks
 
The primer bulb does not need to stay hard once the motor is running !!------The bulb is a manual fuel pump and goes hard when carburetors are filled with fuel and float valves are closed.-------When motor is running fuel level drops a bit and the common man can give the bulb a sqeeze before it goes hard again.--------Test that out if you like.
 
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