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89 Mariner 45 hp problems

C

csimpson

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"My motor starts and idles jus

"My motor starts and idles just fine, but when I give it more throttle the motor actually bogs down. When the boat is out of the water and hooked up to a water hose the motor opens up fully. As soon as it gets in the water the problems start to show up. Someone please help me. I have had the carbs. rebuilt and I have no problems in the gas line. I don't know what to do. I would also like to know what pitch my prop should be. Someone told me to check it. Thanks."
 
A motor with no " load &#3

A motor with no " load " will always rev up and running a motor on a hose to check that proves nothing.Try opening the low speed jets 1/8 turn at a time to see if the bogging goes away.Hook up a timing light and check to meake sure EACH cylinder is firing.Remember that your motor could be running on 3 cylinders.
 
"Chris, I can run some numbers

"Chris, I can run some numbers in a prop calculator for you if you post the make/model/length of your boat. However, if this problem is just "new" it will not be your prop causing it to bog...."
 
Thanks to everyone for the use

Thanks to everyone for the useful information. I hope it helps. I will check my timing and adjust the jets. In response to the prop size: I have a 1982 15' Phantom fiberglass boat. It has a 45 h.p. Mariner motor on it and the problem has existed since I bought it as a repo. It currently has a 13 pitch prop on it. I would appreciate any information you can give me.
 
"Timing on these motors is fix

"Timing on these motors is fixed, you need to use the timing light as an information gathering / testing device.Check the firing on each cylinder as you speed up, no flash means no spark on that cylinder."
 
"Chris - quick run of your num

"Chris - quick run of your numbers - 13 pitch is ideal for that set-up. If you tend to run on the "light side" of overall weight capacity (persons/gear), you could move up to a 15 pitch and still get good results..."
 
Thanks guys. Your information

Thanks guys. Your information is much appreciated. I can't wait to put it to use and get that motor running. I am tired of going about 10 mph. I will let you know what I find out. One more question for now. The local marine store sold me gapless spark plugs to put in my motor. Do you recommend those kind of plugs?
Thanks again.
 
who rebuilt the carbs? when ru

who rebuilt the carbs? when running at whatever full throttle you get look down each carb with a flashlight to see that fuel is being drawn thru the venturi. lack of fuel is a plugged high speed jet. this should be done with a load on the motor.
 
A good friend and I rebuilt th

A good friend and I rebuilt the carbs. He worked on 2-cycle engines for a living. I am going to take the boat to the water this weekend and try all of the tips everyone has provided. I will check for fuel thru the venturi. I will let you guys know. No one has answered me about my spark plugs. The local marine store sold me gapless spark plugs. Are those recommended?
 
"Chris,

I am having the sam

"Chris,

I am having the same issues with my 45hp Classic 50... Runs fine at half speed. Dies at full throttle... If you found the answer please let me know..."
 
"Chris, don't have a manua

"Chris, don't have a manual on your model and Merc was no help on the plugs - personally, I don't have alot of faith in the gapless plugs, pariticularly in the lower horsepower motors.

They ususally didn't come that way from the factory. I would ask the local marine what NGK plug that motor originally had. Mercs of this hp/vintage were made to run on standard NGK plugs..."
 
"Thanks for the information. W

"Thanks for the information. Weather kept me from working on the motor this past weekend, but I am going to try and make it work this week. I will let you know."
 
"Okay guys, I need help. I fin

"Okay guys, I need help. I finally got to take the boat to the lake and give it a try. I adjusted the carburetors and the spark plugs are firing properly. I couldn't round up a timing light, but I discovered that the motor is getting more gas than it can burn up when I accelerate. Just for the heck of it, I partially pinched off the gas line and after about ten seconds the motor picked up and took off momentarily. Obviously the motor died shortly due to lack of fuel. The idle is now better than ever. Someone told me that my problem may be the reed valves. What is the consensus on that suggestion?"
 
I am definately a novice at th

I am definately a novice at this stuff. I am just trying to rule stuff out. I will check all of my cylinders. What would be causing a carb to flood? Sorry for the lack of knowledge. I just know the very basics.
 
"to ruel things out you can no

"to ruel things out you can not skip a step. Compression, spark, then fuel. Get that timing light, put it on each plug wire and check for spark. If spark and compression are good then we move to the fuel system. With engine off, pump fuel bulb, if fuel is dripping out of a carb then they need to be torn down, cleaned, and air passed thru all jets to be sure they are working.If the carbs have been sitting for a year or more they must be cleaned. Warning-running the engine with a plugged jet will cause dammage do to lack of oil. Simply cleaning the carbs or looking at them is not enough, main jets must be clean. http://i129.photobucket.com/albums/p232/beckerjs/FuelProblem.jpg""
 
not-a-student said:
A motor with no " load &#3

A motor with no " load " will always rev up and running a motor on a hose to check that proves nothing.Try opening the low speed jets 1/8 turn at a time to see if the bogging goes away.Hook up a timing light and check to meake sure EACH cylinder is firing.Remember that your motor could be running on 3 cylinders.
Click to expand...
That was happening to mine. Rebuilt carbs, replaced fuel lines, it still did the same. It ended up needing a stator. Now its firing on all cylinders.
 
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