I have a starter on a 4 cylinder 80hp Merc which is failing to crank the flywheel with anywhere near enough kick/force (probably a full turn takes around 2-3secs).
The symptoms are like either there is not enough power, or the bushes or something else are gone in the starter, or there is too much physical resistance somewhere in the starter.
If the starter did turn properly then the engine might start (but I don't know as we've only bought it a few months ago yet to have it running).
We installed all the wiring ourselves, so that doesn't seem too likely to be the culprit although I will clean and re-do every connection today.
Can anyone give me some tips about what in the starter could be causing this, or even better have a link to or pdf copy of some manual that can lead me through a troubleshooting process for the starter.
Ideally a guide/manual would be for the correct or a similar starter but I am a bit desperate. A) this would mean it has the correct tolerances etc the parts in my starter can wear to; and B) I found a guide for a car starter but it is very very different with inbuilt solenoid, very complex pinion method for deploying bendix etc etc and thus of limited use.
- What should I grease when I dissemble/reassemble the starter?
- What can I cheaply replace (which the problem could be) other than bushes?
- Do I need special mercury replacement bushes, or will random generic bushes be sufficient? Or are there just certain tech specs to match up on purchase?
- Could the big magnetic cylinder in the starter have lost its magnetism and what can I do about it?
- I bought a new Solenoid, could it be that, or can we rule it out as at least the starter turns VERY slowly?
The odd thing is when we bought the engine a few months ago, the seller put a battery directly to starter to try and start the engine. The engine turned over WELL then (though motor did not actuallly start because ignition etc was not wired up).
The only thing that has changed since then is the addition of a solenoid (previously missing) and wiring in the ignition circuit with key switch etc etc. So hardly anything has changed accept for the addition of these circuits but now the starter will not spin at the correct speed/force.
So to see if starter worked at speed at all, we took the starter off the engine and applied the battery directly to it (so this is similar to the demonstration when we purchased the engine, but starter is out not in) - the starter does spin fast, but my friend tells me it is without enough kick/force to turn the flywheel. (ie so once the friction of flywheel is added the thing barely turns at all). So if my friend is correct, somehow the starter has completely lost most of its kick/force even though essentially all we did was wire in all of the circuit previously missing (large %) and add a solenoid.
The only other thing we changed is migrating from seller's old bangedup jump-pack (ie battery in plastic case with leads to jump car with) to our new same-physical-size jump-pack - could his have had many more amp-hours or something? Maybe? And could a car battery produce so significantly more power the starter might actually fire properly when it doesn't with a jumppack?
The engine is probably a Mercury 800 (even though it has 850 cowling) with serial 8475339, which would fit in the 8067015 and UP category for Mercury 800s.
This is my first engine and although a decent backyard mechanic with cars, this is getting me and my aviation engineer mate very confused, so all help is very gladly appreciated!
Thanks,
David
The symptoms are like either there is not enough power, or the bushes or something else are gone in the starter, or there is too much physical resistance somewhere in the starter.
If the starter did turn properly then the engine might start (but I don't know as we've only bought it a few months ago yet to have it running).
We installed all the wiring ourselves, so that doesn't seem too likely to be the culprit although I will clean and re-do every connection today.
Can anyone give me some tips about what in the starter could be causing this, or even better have a link to or pdf copy of some manual that can lead me through a troubleshooting process for the starter.
Ideally a guide/manual would be for the correct or a similar starter but I am a bit desperate. A) this would mean it has the correct tolerances etc the parts in my starter can wear to; and B) I found a guide for a car starter but it is very very different with inbuilt solenoid, very complex pinion method for deploying bendix etc etc and thus of limited use.
- What should I grease when I dissemble/reassemble the starter?
- What can I cheaply replace (which the problem could be) other than bushes?
- Do I need special mercury replacement bushes, or will random generic bushes be sufficient? Or are there just certain tech specs to match up on purchase?
- Could the big magnetic cylinder in the starter have lost its magnetism and what can I do about it?
- I bought a new Solenoid, could it be that, or can we rule it out as at least the starter turns VERY slowly?
The odd thing is when we bought the engine a few months ago, the seller put a battery directly to starter to try and start the engine. The engine turned over WELL then (though motor did not actuallly start because ignition etc was not wired up).
The only thing that has changed since then is the addition of a solenoid (previously missing) and wiring in the ignition circuit with key switch etc etc. So hardly anything has changed accept for the addition of these circuits but now the starter will not spin at the correct speed/force.
So to see if starter worked at speed at all, we took the starter off the engine and applied the battery directly to it (so this is similar to the demonstration when we purchased the engine, but starter is out not in) - the starter does spin fast, but my friend tells me it is without enough kick/force to turn the flywheel. (ie so once the friction of flywheel is added the thing barely turns at all). So if my friend is correct, somehow the starter has completely lost most of its kick/force even though essentially all we did was wire in all of the circuit previously missing (large %) and add a solenoid.
The only other thing we changed is migrating from seller's old bangedup jump-pack (ie battery in plastic case with leads to jump car with) to our new same-physical-size jump-pack - could his have had many more amp-hours or something? Maybe? And could a car battery produce so significantly more power the starter might actually fire properly when it doesn't with a jumppack?
The engine is probably a Mercury 800 (even though it has 850 cowling) with serial 8475339, which would fit in the 8067015 and UP category for Mercury 800s.
This is my first engine and although a decent backyard mechanic with cars, this is getting me and my aviation engineer mate very confused, so all help is very gladly appreciated!
Thanks,
David
