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motor hard to turn over?

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geo010704

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My 75HP mariner is really hard to turn over. If I turn the key and use the pull start at the same time it gets easier but still doesn't start. I thought it might be seized but I removed the plugs and the motor was turning over freely.

Any advise on where I should start?
Cheers George.
 
Battery fully charged? Check all your grounds,wipe with sandpaper to shiny and make sure they are tight. Starter brushes worn?
 
Hi, it can't be the battery or the starter motor because it is hard to pull start also. when I say hard I mean very hard. it will pull a little then stick, then pull then stick until the pull rope has fully extended. I can't get a constant pull to turn the motor over. (same when key starting, turn stick, turn stick).

Thanks for your reply though.
 
It's a 75 hp motor! Of course it's hard to pull start. That's why few motors of that size even have a pull start.

You need to either rebuild your starter, or get another one. Don't laugh, but Amazon.com has god buys on Merc starters. Dig out, via the serial number- the part number for the starter and take a look.

Jeff
 
fastjeff said:
It's a 75 hp motor! Of course it's hard to pull start. That's why few motors of that size even have a pull start.

You need to either rebuild your starter, or get another one. Don't laugh, but Amazon.com has god buys on Merc starters. Dig out, via the serial number- the part number for the starter and take a look.

Jeff
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Hi Jeff, I understand that a 75 is hard to pull start but it was not this hard a few months ago. Now it feels like its jammed but engine is not seized???
 
Hmmmm... I wonder if the Lower Unit is dry and rusted internally. Have you dropped the drain plug lately? If water comes out when you do...

Jeff
 
I changed the gear oil around 3-4 months ago. the thing that gets me is that when I remove the spark plugs the motor turns over with ro resistance at all. It's as though when the plugs are fitted it creates a vacuum which is too hard to turn fast enough to start the motor.

Am I correct in saying that if the lower section ( gear box ) was seized I would not be able to turn the propeller by hand?
 
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The reason I can rule out the battery is because when I bought the boat it came with a small car battery with low cca. when I tried to start the motor with the car battery it was not strong enough to start the motor up so I would use the pull rope instead. I replaced it with a proper marine battery and it would start fine. now I cannot even pull the rope out in one complete motion because it is so "stiff".

When pulling the rope or turning the key the motor will turn then stick then turn & stick etc... never a complete revolution to get it started?
 
I thought it might be seized but I removed the plugs and the motor was turning over freely...I replaced it with a proper marine battery and it would start fine.
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If it won't crank now there are several possibilities: Weak "new battery"...ck the mfg's. date code on it. It could be an old "new" battery that is dying, worn starter brushes or an open field coil, corroded (internally) battery cables, dirty battery connections.
 
Check to see if you have a bad carb leaking gas into the motor I believe that would do it too.to much gas on top of the piston causing it to lock up on compression stroke.
 
If you drain the carbs (remove the brass plugs where the high speed jets are), then crank it over first with the plugs out, then you can be sure it's not flooded internally.

I think you simply need another starter.

Jeff
 
I don't understand why you think my problem is the starter. Taking the starter out of the equation, As I said before I used to be able to pull start this motor with no problems, now I cannot get a complete revolution when pulling. This problem cannot have anything to do with the starter motor.
 
Geo I know exactly what you are saying mine is doing the exact same thing. A few monthes ago I could crank my motor right up with a pull rope, but now when I try to crank with pull rope It is so hard.
 
HUMBLE PIE ALERT!!

After some good advise I chose to ignore, it WAS a flat battery preventing me from starting the motor. many thanks to all who suggested it.

Here is the weird part, it is still hard to pull start! Granted I won't be pull starting it but I would like to know why I no longer can?

I am taking it out tomorrow for some tests on the water (at long last) & we'll see how she pulls up after that. My hope is that it just need a good run to clear her throat & lube the motor up.

Thanks again, shows this forum really does work.

I'll update soon.
 
geo010704 said:
HUMBLE PIE ALERT!!

After some good advise I chose to ignore, it WAS a flat battery preventing me from starting the motor. many thanks to all who suggested it.

Here is the weird part, it is still hard to pull start! Granted I won't be pull starting it but I would like to know why I no longer can?

I am taking it out tomorrow for some tests on the water (at long last) & we'll see how she pulls up after that. My hope is that it just need a good run to clear her throat & lube the motor up.

Thanks again, shows this forum really does work.

I'll update soon.
Click to expand...

Have you Cranked the motor yet?
If so make sure the motor is peeing like it should.
My motor was hard to turn over to and come to find out it was a bad impeller keeping it from turning over like it should
 
Lol, Got the boat on the water,motor running fine, found I have leak! fiberglass repair required. Don't you just love boating!

couldn't really test the motor because it was pushing a boat with the hull full of water!

TRY AGAIN LATER...
 
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