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HELP 1975 Mercruiser 165 hard cranking

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firemanlowden

Member
Have a 1975 mercruser 165 cran

Have a 1975 mercruser 165 cranking hard. I took out the plugs and lubed the cylnders with oil and let sit for 24 hours. loosend it up very little still cranks hard without plugs in. If plugs are in when it hits compression stroke it stops. I am useing a car battery that has a full charge. I even used a battery charger hooked up to it at the same time. I know it has sat for 2 years without beeing started. and was properly drained. How do I fix this problem. is there a differance in useing a car baterry vs a marine battery?
 
"Sounds like you have a bad el

"Sounds like you have a bad electrical connection somewhere, or a bad starter. The commutator and brushes in the starter may be dirty. Check all your main heavy battery wires and connections for corrosion. Replace if in doubt. Car and marine batteries are very similar, and it should start.
If in doubt, try turning it over by hand with a socket on the damper pulley nut, with the plugs out. That should turn out to be quite easy to do if all is well.
Rod"
 
thanks I will look at the cone

thanks I will look at the conectors and if not that test the starter. if not that see if cranks over hard by hand. I know its not because of the outdrive because I took the whole thing off to reduce resistanse thinking that might be it.
 
"Shaun; If you are getting suf

"Shaun; If you are getting sufficient power to the starter, having the drive on should not be an issue. My bet is you are not getting sufficient voltage to the starter for some reason.
You can put a multimeter between the main feed terminal on the starter solenoid (where the big wire from the battery connects) and ground. Then have someone hit the starter and watch the voltage. Any less than 8 or 9 volts while cranking indicates too much loss somewhere.
(Wow, I just realized I am over 200 posts on this site. That's a lot of accumulated BS over a short time! Time flies when you are having fun........)
Rod"
 
"I had the same problem when I

"I had the same problem when I first got my new used boat, turned out to be a bad dual battery switch. I bypassed that and it worked fine. but not before I stripped the plastic ring gear in the starter"
 
thanks for the help guys but i

thanks for the help guys but it is still cranking hard. Today I took the starter to orreilly aut parts and had it tested on there machine. It passed with flying colors. I then bought new battery terminal connections and added a 2nd battery also. I am getting plenty of juice to the starter. It turns over a little faster but not much. I had it pop off one time using either for about 2 seconds. But still have the delema of not turning over fast enough to start.
 
My repair manuel says too much

My repair manuel says too much engine friction find problem and repair. UT OH Should I tear down the engine and try to find to problem or not?
 
Shaun:
I would get another

Shaun:
I would get another starter before tearing down the engine. Bench testing the starter w/o the load from your engine only means thier test equipment works as designed.

"lubed the cylnders with oil and let sit for 24 hours". What does the oil look like? 80-90W? I would change the oil & filter and dump in a can of SEA FOAM in the oil and crank the engine to distribute the SEA FOAM to dissolve any heavy varnish/sludge in the engine. Use a 30 wt. oil and put in a new set of plugs since the old ones are now oil fouled.
Guy
 
I gess I will put my two cents

I gess I will put my two cents in here.
First off I too have a 165 Inline 6 engine.
So I know a little about this. And I use my SELOC & Mercuiser Manual to work on my boat.
You already had the starter tested & Electrical system. And it was good. Time to move on.
From what I have read so far it seems your engine might not be the problem.
Pull the outdrive off from the Bell housing.
Then remove all spark plugs. Put a wrench on front fan belt pully. And turn engine Crankshaft.
It should turn with out using a braker bar.
Or you can use the starter for only 5 seconds.
Point is it should turn over easy. DO NOT START.
If after you do this test and engine turn over easy. You found the problem. Your outdrive.
If the outdrive sat for 2 years. Drain the oil. Look for white milky water or metal in the oil.
And you might need to replace the water pump in the outdrive. Or do major work on the outdrive.
Point is the outdrive can slow down the starter.
 
"James:
You have more exper

"James:
You have more experience and knowledge about his engine than I, but he already pulled the O/D and the problem still exists. That is why I think it may be an engine sluge, varnish and weak starter problem. I agree w/your recommending the O/D needing some maint. See all his comments above. Guy"
 
Op's sory. Your right Guy

Op's sory. Your right Guy G. Try what Guy G. said. If that did not work try this.
When you pump out the oil from engine; look it over for water & metal pieces.
Next check the Disribitor is installed right.
Very Long shot check the camshaft timing.
Point is if you put a wrench on front pully wheel and engine will turn with out a lot of force.
varnish/sludge might not be the problem.
TIMING of the spark plugs firing. And Timing of the valves might be the problem.
Or your getting a small amount of cooling water in one or more cylinders as its cranking. Which gives you a Hydralic Lock. Or too much Fuel.
Point is there is alot of things that can cause your problem. Your engine still under warrenty?
You said it was Rebuild? Many people might think just replacing a few parts is a rebuild.
 
"Rebuild or replace the starte

"Rebuild or replace the starter, and make sure your battery connections are good.

Once you get her to fire up--even once--most of your problems will go away.

Jeff"
 
Yes Fastjeff Once he gets it f

Yes Fastjeff Once he gets it fire up his problems will go away.
Since he had the Starter already tested.
Why Fastjeff do you think its the starter?
We can all learn from your answer.
Thank You.
 
Ok guy I have not tried the se

Ok guy I have not tried the sea foam. I may do that. and yes it is a total rebuild too. I can now get it to fire up I just got to prime the fuel line to keep fuel to it. It still cranks hard but not as bad after I let the oil sit in the cylnders for 24 hours. Thanks for all the help guys.
 
"The inline 6 you speak of doe

"The inline 6 you speak of does not have a crank shaft pully bolt. You can see if someone has an adapter to put into the couple to turn the engine over or you will ahve to remove the crank pully and get a crank turning adapter for a small block chevy. Many suppliers have them, Summit and so on. Put a torque wrench on the engine with plugs out and turn it over. If it takes 45 ftlbs to turn it over it is ok. Go for the elec system. Probably the starter."
 
"Shaun: It just dawned on me

"Shaun: It just dawned on me to ask you about the type of field coils in your starter. If it has standard coils, that could be your problem especially since the engine may be tight from the rebuild and the coils can't provide the armature enough current to turn the starter fast enough.

Your starter would need high current/torque coils which can be identified by the lead coming out of the starter that attaches to the solenoid. If there is a single lead or strap then it is a standard coil. If there are two leads or straps attached to the solenoid then they are the high current/torque coils your starter needs.

A starter shop can change your coils easily if needed. Guy"
 
"Hey! Is that one of those st

"Hey! Is that one of those starter setups that bolt upward? If so, it might simply need to be properly shimmed.

Are the bolts that install it vertical upward?

Jeff"
 
Shaun:

I traded my 20 yr

Shaun:

I traded my 20 yr old starter in for a reman. I had the shop tech. open it up and check it to make sure I was getting the right field coils. It will make a difference when it cranks.
Guy
 
Hey guys thanks for all your h

Hey guys thanks for all your help. I have it running and runs good After the fist start it started over and over again no problem. Now time to fix the lower out drive. dont know whats wrong yet. dont go into gear. Top is in perfect shape.
 
Well I ended up useing PB Blas

Well I ended up useing PB Blaster penitrating oil. the best stuff you can buy and let it sit for only 10 min and loosend everything up in the cylyders. worked great. After useing that I changed the oil imediatly just in case any got into the oil.
 
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