Logo
FULL SITE MENU

Mercrusier won't turn over

n36511

n36511

Regular Contributor
Need a little help. 2005 4.3 thunderbolt. Went to crank it and it won't turn over. Here is how it plays out:

turn key to on
buzzer sounds
gauges activate
gauge reads just under 12volts
turn key to start
nothing. No clicks. No sounds. Nothing.
While turning to start volts drop to 10 or so.

Moved shifter several times, tried again, same results. No clicks yet voltage drops like it is trying to do something.

Where would you guys start?
thanks,
Scott
 
Ground at battery looked good. Will have to trace it and the positive to see the other connection points. I thought it would at least click though even with bad connections??

thanks for the quick response!
 
what about the ground at the block, what about corrosion at the starter bolt, what about corrosion at the 50A CB
 
Thanks for the replies. The boat is about an hour drive for me so just trying to get all of my ducks in a row to minimize the number of trips needed to resolve. I will start at the battery and work my way through all of the connections. When it comes to jumping the starter directly, I jumper between the large positive terminal on the starter and the small terminal that appears to have a purple wire plugged into it in the attached pic? Also, it appears the previous owner bypassed the fuse? Sorry for the ignorance. I dont work on boats often enough, so I lack a lot of knowledge.
Starter.png
 
No, you need to remove al the wires, clean them and replace the starter
The starter was under water connected to a hot battery and is finished. The plastic square block is the 90 amp link .If it has only a orange wire , that comes from the alt output, if it also has a Red wire, thats the main system power
 
Thanks for the insight. That is likely to save me a whole lot of time. For my education, what in the picture gave away that the starter was underwater with a hot battery? Oh and I am not questioning it....it is likely the case. The boat was in an uncovered storage lot in S FL when Irma came through. The drain plug was out, but when I arrived, only a small trickle of water was exiting the drain. Upon further inspection, debris from the storm had blocked the drain.The water line was not up to the base of the engine, however I didnt make it to the boat until a week after Irma passed through. I am just amazed that you can look at it and tell that happened.
 
You need to define "to the bottom of the engine" .Looking at the corrosion of the starter terminals "the green stuff"
indicates battery action. That says water was up to the middle of the flywheel . If the starter was under than I would drain the oil pan first to make sure no water is sitting in the pan.

Next I would pull the drive to see if any water got into the bellow from the bottom vent hole. Trapped water will cause U joint failure and gimbal bearing failure.
The seals are meant to keep oil in but will allow water to enter also.
 
Thanks for the continued feedback. I have ordered a replacement starter and will go over the contacts and wiring when i visit the boat again. I will update this thread with my results.
 
make sure to check the oil level before starting, if above full mark then suspect water in the pan. Pump a sample from the dipstick tube .If you do find water in the pan you most likely also have water in the bellow
 
Back
Top