Help starter motor issues!!

[ribless]

I am after some ideas/suggestions as to what could be the issue...here goes:

The engine is a Mariner 115hp, 4 years old. When you turn the key you hear the click of the relay switch and the starter motor pops up onto the flywheel, however it does not turn. If you hook a portable jump pack to the battery the same issue arises, however if you hook the portable jump pack straight onto the starter motor the engine starts.

The battery is fairly new 1-2 years, in good condition and fully charged, all the other electrics on the boat work. The connections at both the engine and the battery end are tight and well connected and no fuses have blown. The ignition is also fairly new and as the starter motor pops up onto the fly wheel i imagine we can take it as a safe bet thats not the issue.

The only thing left which i can think of is the main cables between the battery and the starter motor, the cables above deck look fine.....does this mean i am going to have to pull the cables up from below deck to check their state or could i have over looked something?

Many thanks in advanced

[PeterM]

Welcome to world of Ribnet !

I'd say you are pretty much there on what you think is the problem , but prior to pulling cables through - is there main swith that could be corroded , or if thats ok , try cutting an inch of insulation off the wires ( before you start pulling ! ) to see if they are visibly degraded by corrosion. It only takes a tiny amount of corrosion to cause sizeable drop at the engine ( for me from 12.4v down to 5v ! )

If the switch & both cable ends look OK I have no idea, but I have had a very similar thing on a boat that was due to it being swamped once - water got in the cables then over several months things got worse & worse to the point where it would notturnover fast enough to start.

I replaced the batteries ( needed doing anyway ) , changed the switches ( no improvement) then finally had to consider cables. Been no problme ever since & starts much more 'cleanly'.

[doggypaddle]

if the starter pinion pops up but the starter doesn't turn then its most likley the starter solenoid contacts.
if it was the battery or cable the voltage at the starter solenoid would drop as the starter engages, and cause the pinion to drop down again, making the voltage rise again, causing the charactersitic click,click,click,click, you get with a flat battery or poor battery cables.

connect your meter from earth to the main terminal on the starter and check the voltage at the terminal when turned to start, if its 12 volts then check the terminal the other side of the solenoid where the cable goes into the starter itself, if thats not 12 v too then the solenoid contacts in the base of the solenoid are the problem.

[King_C]

Whoop! Remembered my login!

I reckon its the cables!

We need a multimeter!

[doggypaddle]

Originally Posted by King_C

Whoop! Remembered my login!

I reckon its the cables!

We need a multimeter!

If it starts using the key as normal with the jump leads connected to the live side of the starter solenoid then i would agree its the cables or crimp connecteors on the end.
Keep the key turned for an extended period then feel for something hot, if you find a hot spot

[9D280]

I'd also do the voltage test both sides of your battey switch (if you have one).

My old SR the switch was mounted quite low in the console, and it got dunked once when I forgot to lift the trunks & went for lunch..... Started fine, & drove off wioth the trunks working the way they should, and over the following week it got progressivley more reluctant to start until I got lots of excersie with the recoil starter....... One new switch later......

A lot of those batt switches are a joke considering they are classed as "marine". On the current boat it sits well above the "swamp line".

[King_C]

I would have thought the batt switch is ok as it was replaced only a couple months ago. Also the engine trim and a few other things run thru the switch and theyre all working fine. Obviously there could still b an issue with lower voltage getting thru the switch.

Altho...I think its a NO voltage problem rather than a LOW voltage problem as the starter gear isnt even turning when theres no pressure on it from the flywheel.

[doggypaddle]

where does the B+ feed for the ignition switch come from then? usually its from the main starter solenoid terminal, in which case there must be voltage there to pull the starter pinion in, or does it come directly from the battery?.

[9D280]

Remember some starters just use momentum & the "no load" accel to shove the starter gear up the shaft on a giant screw thread. There could be enough to do that, but not enough juice once it engages to actually turn the engine.

[jambo]

Hi Ribless
I have just had the same problem with my mariner 150 over the last two years just herd that annoying clicking then after about ten turns we might get a start!! Check everyting and we eventually found the culprit!! In my ribcraft everything goes thru a trunk under the deck from cosul to engine and it was the cables they were 60% corroded especially the neg therefore the starter was not getting what was in the bat and therefore not turning. I would check them out.

J