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Help with MarinerMagnum 40hp

N

Nightmare

New member
HI anyone out there to help me, Have a magnum 1992 40hp that just wont start by herself. New battery fitted, new starter motor and new solenoid. The motor turns over no problem with spark plugs out but if you put them in is reluctant to start by key unless you give it a helping hand (with rope to flywheel) then she runs no problem. The starter motor engages the flywheel but struggles to turn, could this be down to compression? have no compression test kit.Any ideas? thanks in advance for the help.
 
Internally corroded battery cables can cause a loss of amperage to the starter. Do any of the cables get hot?
 
Just repaired a 50 hp Merc starter that did the same thing. All it needed was sanding the commutator nice and shinny clean, and lubing the bushings in the starter. Spins over super now.

Jeff
 
Thank you for the replies, found the cause and she is working beautifully now. The battery wire was badly corroded at the connection, unfortunately hidden by the rubber protective shroud, recut and fitted new terminal connectors, jobs a good un.
 
guyjg said:
Perfect...glad she's fixed.
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Hi Guyjg, back again with similar problem. After changing the battery connection she was firing up first time everytime. Now two weeks later I can't get her to turn over at all. The starter motor spins but the engine doesn't engage. With plugs in or out she doesn't feel like turning over. Any ideas?
 
Did you check for spark? The engine needs to spin quickley to produce spark. Check both ends of both battery cables.
 
HI guyjg, no spark. Wouldn't matter anyway as engine isn't even turning over with or without spark. Like I said the starter motor spins but it doesn't engage the engine to make it spin quickly. Is there something I need to check before the spark?
 
The starter has to have sufficient amperage to thrust itself into the flywheel gear. You should be able to move the starter gear on the shaft w/your fingers...key off. Revisit post #4 again.
 
Sorry for the late reply been away for weekend. The starter motor was lifting ok with key and separately through additional leads from battery, unfortunately I now have the dreaded click and I only fitted a new solenoid and starter 3 weeks ago. I will have to get back to basics and do amp test across all components and wire checks again.
 
Your starter cables are 21 years old. You had a previous problem w/corrosion in the + starter cable. If it were mine I would get a new starter ground and positive cable from the starter to the solenoid.
 
Reread my above post on rebuilding your starter. That's the FIRST thing you should done. It's dragging, causing your other problems.

Jeff
 
The starter is brand new, just fitted month ago. I can understand what you say about the cables guyjg but after testing everything on multi meter and checking all connections and cable itself everything is ok to the starter motor. That lifts up but the engine will not engage, previously the engine would turn? Does the stator have anything to do with turning engine?
 
Does the stator have anything to do with turning engine?
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NO. The keyswitch turns on the solenoid which sends power from the battery via its cables to the starter thru the starter cables. A slow or non-functioning starter should be caused by a weak battery, defective starter, defective solenoid or defective battery and starter cables. Take your pick. A new starter only means the paint is new until it is proven to work.
 
Like your terminology!!! the starter motor paint had dried and was running ok. Forgive me for being stupid but I can't get my head around why the flywheel won't turn. As I said everything up to the starter is ok 1. Battery tested under load with battery tester 100% ok 2. New starter ( no clicking) 3.new solenoid (no clicking) 4. 12.6volts through cable either side of battery and starter motor, 12.6v on solenoid, If I fit new battery leads to starter the same thing happens, starter spins but bendix gear does not engage flywheel, bendix gear lubricated. I will replace the cable from solenoid to starter motor and test again, anything else you can think of ? this is driving me mad. many thanks for your help so far
 
Make sure there is bare metal where the starter is grounded...new starter has fresh paint. If there is no ground strap then the starter mounting holes need to be bare metal.
 
Finally working, replaced battery cable to engine and cable from solenoid to starter and renewed all connections bare to metal again. Thanks for all the advice. Whatever it was I don't know but it will be left as is.
 
I hope the problem doesn't return. It happens that way sometimes when you didn't definitely identify the problem.

Jeff
 
I agree w/you Jeff...I had a cracked + automotive cable head on a starter battery. Start/no start issue came and went until I decided to pull the battery and only found it when I retightened the connection.
 
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