90 HP Mercury: Trouble Starting

[NEPAboater]

I have a 1996 StarCraft Superfisherman. Been having trouble starting it. The compression is good, I changed battery (volts are good), spark plugs, fuel filter, solenoid, key start ignition switch & gas is new w/treatment fluid. Before/after this, it's always the same thing: Everything powers up and it turns over. It won't start though, and eventually, it doesn't even turn over. Anyone have any ideas of what this can be?

 

[racerone]

When these motors do not turn fast enuff there will be no spark.------" eventually it does not turn over " is what you say.-----Start with having the battery load tested.---Then take starter apart for inspection / service / new brushes.----Starter is elegantly easy for a novice to work on too.

 

[ondarvr]

You may want to explain your normal starting method too, details are important, it helps in providing you with a good answer.

 

[NEPAboater]

I'll test the load again, but it was recharged just prior to my last restart attempt. It was recently holding 13+volts day-to-day. I'll see if I can do what you say regarding the starter. I don't think it has to do with my normal starting method (priming bulb, choke, placing in throttle mode, etc) since I tried many variations, none of which work.

 

[ondarvr]

Letting us know your method can help to identify an issue with your technique, or with something not working. The Choke is not an actual choke, it's a primer valve that allows some fuel to flow into the intake when starting cold, it needs to be manupulated correctly for easy starting. If the primer solenoid doesn't work correctly it can make for very hard starting.

The voltage under load is what's important, a good battery shouldn't go dead quickly, but you didn't indicate how long it takes to drain it down.

 

[NEPAboater]

I understand. That's what I meant, the primer. The solenoid was just installed, but the boat had the same problem before that. I just tested the voltage and its at 13. So, it appears that the battery isn't draining quickly.

 

[racerone]

Have the battery LOAD TESTED at a shop / automotive supplier !----Just had my truck battery tested before cold winter days leave me stranded.

 

[Barnacle_Bill]

Another possible problem is corrosion in the battery lugs. It can build up in there where you can't see it and cause starting problems. Do a voltage drop test on them to make sure they are good.

 

[roscoe]

Do you have spark at the plugs?

Gas getting into cylinders?

 

[Texasmark]

Put your voltmeter leads on the red power input stud on the starter and the other lead on the black wire attached stud. Spin the engine in the normal fashion. If you don't have 10v or more chase your supply circuit including solenoid, dirty connections.....inside where the current flows, corroded cable-cable lug attachment interface and last load testing your battery. Unless you put a load on the battery that will draw a couple hundred amps and read the terminal voltage of the battery for at least 11v, you know nothing about your batteries condition! Older sulphated up batteries will charge up to the desired voltage although monitoring the process seems a bit odd from what you get on a good battery. Problem is, the sulphate adds internal resistance between the cells and when you ask for current delivery, they develop a large internal voltage (couple of volts or so) which starves whatever you have connected to the battery asking for amps.

If you pass that test go after your starter like racerone said.

 

[enginepower]

Does this have fuel richen solenoid (choke) solenoid)? If so, may want to make sure it's working. Mine won't start without it. I have a 95 model 90hp and with cooler weather, I have to hit choke a few times (while it's running) until it warms a little. I have a hot foot but even giving it throttle, engine will bog and stall. Warm weather, don't have any problems.

 

[Texasmark]

Does this have fuel richen solenoid (choke) solenoid)? If so, may want to make sure it's working. Mine won't start without it. I have a 95 model 90hp and with cooler weather, I have to hit choke a few times (while it's running) until it warms a little. I have a hot foot but even giving it throttle, engine will bog and stall. Warm weather, don't have any problems.

My '02 90 was exactly the same way. Really cold natured and I spent a lot of time ensuring that everything was up to snuff on the engine including fuel, oil, and additives. My main aggravation was the first hole shot of the outing. Guarantee you, every single time, regardless of how much time I spent putting around the no wake zone to warm it up, punch out was a coulgh, belch, fart, maybe one is hitting or is it two , bla bla bla. Once on plane, firewalled, it took another 30 seconds to quit coughing up phlegm but after that, ran like a dream the rest of the day, got my 5600-5800 constantly, and on cold days my underside of 50. Stop to fish and it would restart faster than I could get my fingers off the key. Couldn't ask for a better engine......but that initial operation was always a bummer. Course I didn't go out every day and that was surely part of it. It would sit in the shop for a couple of months some times.

 

[Oldcraneguy]

I think the first thing I would do is isolate the problem, Fuel or Fire..Im not familiar with your engine but in most cases you should be able to get a squirt bottle with a straw to the air inlet so you can get a shot of gas to it. If it tries to run you have fuel problems if it doesnt look at spark... meanwhile be aware that a weak yellow/orange spark in the atmosphere can equate to no spark under cylinder pressure....OCG