3.7lx merccruiser starter issues.

[Frontier2002]

Hi all .
I'm in need of some help to get boat up and running for the season .
I have a 28'carver with twin 3.7 lx motors .
One was a fresh rebuild last year and just reinstalled a freshly rebuit motor a couple weeks ago..
Ever sense I owned the boat it rolls over slowly barely fast enough to start it ..
Batteries were getting weak so replaced wit 3 new 1,000 cc Batteries and replaced bolth starters cleaned every connection on the motors I could find but still not getting any better..
Same issue with bolth engines ..
Could it possibly be the perko transfer switch causing the issue ??..
Even when switch is set to all it doesn't make any difference..
I thought 3,000 cold cranking amps would make a difference but does not change ...
Thanks

 

[kenny nunez]

Do you still have the Prestolite starters?

 

[Frontier2002]

It's a Wilson brand
Dr 10 Mt

 

[kenny nunez]

They look like a good product. Are all the cables the same size? Is the battery switch original with the boat? How and where are the ground wires mounted ?

 

[Frontier2002]

They look like a good product. Are all the cables the same size? Is the battery switch original with the boat? How and where are the ground wires mounted ?

Yup all wires are the same size .
They are grounded to the back of the block
Although these are aluminum blocks do you think that might have something to do with it?
And the battery switch I do believe is original to the boat which I think is a 1988ish

 

[Scott Danforth]

clean all connections to bare metal, shine it up with 150 grit so its shiny and clean enough your mother-in-law will eat off them.

then once they are tight, seal with marine electrical varnish.

3000 CCA means nothing if its crossing a bad connection.

 

[Frontier2002]

Didn't sand them but polished them with a heavy grit scotch pad thing on the end of a drill they were super clean ..I like the varnish idea and will do that once I have this figured out .
I going to pull factory battery switch out tomorrow and see if there is any issues with the connections on it.
Is there a way to test the internal connections without taking it apart.?

 

[Eric 3.7LX Alpha 1]

As a test, you may be able to connect a jumper cable from the POS on the batt to the large lug on the starter that the battery connects to....and also the NEG to the starter body, and see if it cranks over any faster. Be careful that that red cable doesn't touch the motor or starter body at all except that lug. If it's noticably faster, remove one and see which makes it faster...

 

[kenny nunez]

Can you post a picture of the area of the starter and the boost solenoid connecting wires?

 

[Frontier2002]

Still no farther ahead
Pulled perko switch and eliminated the second factory fuse as there is one already attached to the donkey **** cleaned all the connections on perko switch but still no better..
Could the internal of the switch be the cause as it does the same on each motor so thinking its a bad /broken ground or the switch is not making good contact inside ..
Going to run 2 new ground wires directly to starter bolts from battery which should eliminate if it's a bad ground ...

 

[Frontier2002]

 

[Frontier2002]

 

[kenny nunez]

When you had the starters rebuilt did it make any difference on the cranking speed? How long have they been on the engines?
I hope the battery switch replacement helps.

 

[Frontier2002]

Bolth brand new starters.
Think I found the issue found a broken ground wire and now 1 motor is cranking nice and fast .
Have second motors waterpump apart to replace the seals so hoping it has resolved the issue with that one as well