1972 100hp Very slow turning over

thejeepster02

Petty Officer 2nd Class
Joined
Jul 22, 2004
Messages
129
My old Rude is giving me troubles again..
trying to start, it acks like the battery is low, turns about 1/2 way over and stops then 1/2 way again and stops. keeps doing this like the battery needs charged.
I have a fully charged battery along with hooking a 2nd one in parralel to increase the starting power.. no help.
I noticed the prop is turning while im trying to start it. the for,nue,rev switch is in Nuetral and the motor wont even try to start if its in for. or rev.
I did also notice that the throttle can be anywhere instead of in the start position. She has sat out of the water for 1 year, the lower unit was serviced about 4 yrs ago. I just got done replacing the throttle cable and double checked my self to make sure I didnt losin something up.. but who knows.
So, to sum it up, it seems to be in gear and I dont think it should be turning over while the trotal is full.
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: 1972 100hp Very slow turning over

Check the voltage at the starter when trying to start, it sounds like you have either a low voltage problem or the starter is shot. The lower unit has a pump in it, will go to neutral when you achieve starting RPM.
 

kenmyfam

Supreme Mariner
Joined
Aug 10, 2006
Messages
14,385
Re: 1972 100hp Very slow turning over

Check and clean all connections and cables. Check for damage to the cables as well. Dirty connections will cause you no end of problems.
 

kenmyfam

Supreme Mariner
Joined
Aug 10, 2006
Messages
14,385
Re: 1972 100hp Very slow turning over

C&P from JB


Remove and clean connections on battery-to-solenoid cable, battery-to-engine block cable and solenoid-to-starter cable. While they are off, inspect each for corrosion, broken insulation with corrosion and weak points.
Replace corroded or weak cables.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: 1972 100hp Very slow turning over

90% of starter problems are bad connections. remove and clean both ends of the battery cables, so that they are shiney, also the cable from the solenoid to starter. check for nicks in the cables. and make sure the connectors are on the wire good. the cable tend to corrode from the inside out, if nicked, corroded wires, and connections, heat up and cause resistance to the follow of electricity, thus the starter doesn't get enough. you can also take jumper cable pos battery post to large post on starter. with a good connection, the engine should spin. then if the starter is good clean everything and retest. then trouble shoot solenoid. starters can be rebuit at a starter/alternator shop, much cheaper than a new one.

also have the battery load tested at the auto parts store, free, i've had new batteries go bad
 

thejeepster02

Petty Officer 2nd Class
Joined
Jul 22, 2004
Messages
129
Re: 1972 100hp, Props turn while starting, Very slow turning over

Re: 1972 100hp, Props turn while starting, Very slow turning over

I thought it was electric solenoids that changed the gears, not oil.
Can you explain
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: 1972 100hp Very slow turning over

The solenoids control the flow of fluid from the pump in the lower unit. It takes pump pressure to shift into neutral and reverse. When the motor reaches cranking speed there is enough pressure to go into neutral. If you would loose voltage or pump pressure in the lower unit it will stay in forward. I have found it a good idea when coming into the dock or other tight spaces, shift into neutral for just a second and make sure yopu have it. I have seen more than one boat hit the dock because of lower unit problems that the owner didn't even know he had.
 

thejeepster02

Petty Officer 2nd Class
Joined
Jul 22, 2004
Messages
129
Re: 1972 100hp Very slow turning over

Makes sense, I was thinking of push pull Mechanical, buts its really a solinode valve

Thanks, I have enough info now to make some checks
 
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