Starboard Engine Slow Crank, No Start

[Kernel]

Just want to run this by the peanut gallery before I drop money on a new starter and pull the header to replace it.

2017 AR240, 185 hours, zero issues to date. I’ve done all my own maintenance as per the recommended schedule using Yamaha products. I’ve got the extended warranty, but the closest dealer is a good 2.5 hour drive and I don’t feel like being without the boat for as long as it would take them to get around to fixing it in the middle of the season.

Both engines started fine on Sunday when I put it in the water. Spent the day at the beach, getting ready to head home the port engine started fine, went to start the starboard and immediately knew something was off. Getting 250-300ish RPM during the crank, it turns over a good 3-4 times slower than the good engine. I want to say the port is 950-1200 RPM on crank and fires straight up. Let it turn over a good 5-6 times with no joy. Waited a bit, tried again, no joy. Checked the impeller clean out port, clear. Put on the goggles and got under the boat, clear. Decided to limp home and see how it would do out of the water.

Since putting it on the trailer I’ve checked the air filter and plugs, all appear to be in very good condition. No evidence of oil or water in the air box. Cranked the engine with all four plugs and air filter removed, issue persisted. Did note that the plugs were wet when compared to the plugs from the good engine. Smells like fuel. It does look a bit dirty down in the spark plug holes, but about the same as the good engine and I am no mechanic, so I have no idea how “clean” it should look.

Checked for corrosion at the battery, grounds, and connections to the starter, all appear very clean and free of corrosion. Checked the volts coming from the relay while cranking with the kill switch pulled and it matches the good engine. Getting a max reading of about 8.5v from each, which seems a bit low, but I’m not great with a multimeter and since it matches the good engine I figure it means everything from the battery to the relay output checks out. Also swapped the relays, issue persisted on the starboard engine.

Removed the pump housing and impeller to check for binding. None noted and the engine still cranks slow with the impeller and housing removed.

Best guess is that the starter is bad and can’t produce enough torque to turn the engine fast enough to light off. 200ish hours and 4 years seems like a reasonable amount to expect from a starter I suppose. Though we don’t necessarily turn the thing off and on all that much. Kiddos are still too young for wake sports, so we mostly go to and from the beach/sand bar and look for dolphins, #girldad. Thoughts?

 

[Beachbummer]

One of my starters is weaker than the other but it only shows when the battery voltage is low. Since the other engine runs... can you try starting it with the other engine running and revved up just a bit? It might just start. Wild thought. might be a 20 second test may not need cooling water if you are fast. Just to discount slightly weak battery and weak starter combo.

 

[Kernel]

One of my starters is weaker than the other but it only shows when the battery voltage is low. Since the other engine runs... can you try starting it with the other engine running and revved up just a bit? It might just start. Wild thought. might be a 20 second test may not need cooling water if you are fast. Just to discount slightly weak battery and weak starter combo.

Good idea, I’ll give it a try in the morning as to not tick off the neighbors tonight. Did try with the both batteries in the emergency cross tie or whatever it is called, that didn’t seem to make a difference.

 

[Kernel]

Tried to start the malfunctioning engine with the good engine providing some power, no change. I was wrong about the RPM on crank though. Good engine is about 260 RPM, bad engine is about 140 RPM. Was able to get a decent pic and definitely noticed some corrosion on the starter. Going to change it out and see what happens.

However, I think the Yamaha brand is overpriced. Cheapest I’ve found is $440 and I can get an off brand that appears identical for $150. Guessing Yamaha doesn’t cast its own starters and a generic brand that looks the same is probably manufactured in the same factory as the “Yamaha” brand.

 

[WREKS]

Edit and delete last post:

I won't still test the starter by using jumper cables directly to the battery if that is possible.

Should be, I would still test the starter by using jumper cables directly to the battery if that is possible. Also, service manual has service points for starter. May be able to fix it if needed.

 

[Kernel]

Yeah, trying to get my hands on a pdf without paying the $75.

 

[WREKS]

Not your year or model but is a 1.8 litre

 

[Kernel]

Pulled the header today to get to the starter. That was a bit of an adventure. Disconnected the three wiring harness couplings, a couple of water hoses, 8 short 12mm bolts, 3 long 12mm bolts, and the one 14mm bolt hiding around back. Lot is corrosion on the quick connector water hose clamps. Think I’ll swap those out for some stainless steel worm gear clamps.

Once the header was off getting the starter off was relatively easy. Disconnected the one hose that was in the way of the two 12mm bolts holding it on, one of them also connects the ground to the starter. Removed those and the 10mm nut holding the battery wire to the starter.

Got the new starter on, reconnected the battery and the ground , went to turn it on and all I got was a click from the relay. A bit of troubleshooting later and I am fairly certain that I got a bad starter. SMH. Pulled the new starter out, connected the positive and negative, turned the key and just get the relay click. Same process for the old starter and it at least spins.

Project half done for this weekend. Hopefully I can get a new new starter by next weekend and we’ll see if that solves the issue.

 

[Beachbummer]

You can use your car battery and jumper cables to run the starter direct from your car and confirm your diagnosis. The relays go bad too.

Mine clicked but did not provide power.

 

[Kernel]

After some troubleshooting with the multimeter I think I can rule out the relay and I’m still fairly certain it’s a starter issue.

Getting 12.5V from the starting battery. Not bad considering the number of times I’ve used it to crank both engines without running the boat last weekend. Starboard (malfunctioning) engine shows 12.3V to the starter. Port engine shows about the same.

Disassembled the old starter and cleaned it before putting it back together. While I learned a lot about how a starter functions the old starter still cranks the engine far too slow. With the headers removed I can at least see that each cylinder is firing and rule out excessive back pressure as the culprit. Got another new starter on order. We’ll see what happens when I get it installed.

 

[Kernel]

BLUF: There is a diagnostics page on the touch screen that I never knew existed. Boat still isn't fixed, but I'm growing more confident that the starter is the culprit.

I'm somewhat ashamed to say that here I am over a month in, during the summer, and the boat is still out of service. At this point I'm just using this forum as a journal in case anyone else ever has a similar issue, but feel free to chime in if you have any thoughts.

Still waiting on replacement starter number 2 to arrive. I went with an SBT this time instead of the cheap-o eBay option. While I'm waiting for it to arrive I decided to do some troubleshooting just to rule out any other causal factors. Some of this is "no duh" to anyone familiar with engines, but maybe it will be useful to anyone who is not.

1. Cleaned both sides of the negative lead. It is a solid black cable that runs from the starter and the cranking battery.
2. Cleaned the negative battery terminal on the cranking battery.
3. Performed a voltage drop test on the negative lead with a multimeter.
4. Performed a voltage drop test on the positive lead and confirmed that I am getting 12.8V to the starter (with a fully charged battery this time).
5. Downloaded a service manual for an older model 240 that I found in the forums here.
6. Bought a hard copy of the service manual from http://www.service-shop-repair-manual.com

Now for some cool stuff.

1. Learned that if you hold the SYS/CTRL button for 3 seconds it takes you to a diagnostics page.
2. Using the diagnostics -> engines page I discovered that when I crank the "good" engine the voltage to the engine drops from 12.8V to 9.8V and when I crank the "bad" engine the voltage only drops from 12.8V to 10.8V.

I believe that point 2. further supports my theory that there is an issue with the starter. For whatever reason, it is puling less draw from the battery than the starter on the other engine. Less draw, less cranking power. Right?

I can't for the life of me figure out what is wrong with the starter itself. I've completely disassembled it twice, cleaned it thoroughly, and done all of the checks called for by the service manual. There is a small amount of corrosion on the exterior of the starter, but the interior is incredibly clean. Clean except for the grease on the planetary and ring gears of course. All continuity checks check good, but given the lack of voltage drop on crank when compared to the good engine, it seems to me that the starter is the most probable culprit.

 

[Beachbummer]

Have you powered either or both of the bad starters directly with 12v from another source? Like a car using jumper cables?

 

[WREKS]

Have you tried ohming the starting circuit from the downstream side of the relay? Should get continuity. The pick was used to pull back the positive cable cover. Metering starter circuit.

 

[WREKS]

I would even check the 20A fuse above it.

 

[Kernel]

Installed the new SBT starter this weekend. Symptoms persist. Rips on crank hang out in the 140 RPM range on the starboard engine. Current state of the engine is pump, headers, and air box removed to minimize anything that could possibly be bogging down the engine on start.

Been getting pretty handy with the multimeter

Battery
12.6v static
10.5-11v during starboard crank (New SBT starter)
10.8-10.9v during port crank ( Original Yamaha starter)

Starboard Voltage readings
9.5-10v Starter during crank

Volt drop test
Battery to relay input .6-.7v drop static
Battery to relay output .7-.9v drop cranking
Battery to Starter input .8-1.0v drop cranking
Battery to Starter ground .3v drop cranking

Port Voltage Readings

Volt drop test
Battery to relay input .6-.7 drop static
Battery to relay output 1.05 drop cranking

Can’t get the multimeter on the port starter input terminal with the header on and I’m not taking it off as I’ve got enough info without it. What stands out to me is the variability on voltage and drop on the starboard engine. Not sure if this is a symptom of the headers being removed or if it is indicative of the underlying problem.

Tried running jumper cables from the battery to the starter just to be sure and the rips are still just as low.

I DID manage to get the engine running, twice. Used a battery booster right after it had been on the charger for a good long while. Took a good 15 seconds to get her to light off, but she did start. Other than sounding real funny with the headers off, it seems to be running fairly normally. At least for the 10-15 seconds I let it run since I couldn’t run cooling water through it with the headers removed. I think that rules out the timing chain that used to be an issue on these engines.

I’m starting to run low on ideas. Even greased the intermediate bearing housing to make sure it wasn’t bogging things down. That was a bit nerve-racking as I was worried about over servicing it and busting the seal.

The quest continues. Going to keep researching, but I may have to start looking at valve clearances and compression soon. SOMETHING is bogging this thing down when I crank it.

 

[Beachbummer]

Can you try getting power to the starter with jumper cables to rule out the wiring? Voltage can be misleading and not show amp/resistance/current

 

[Kernel]

Tried that. Directly from the positive terminal to the starter input and even clipped the negative lead to the battery negative terminal and starter ground. Didn’t look at the tach when I did it, but I can hear that the engine is still cranking just as slowly.

 

[Kernel]

Also cleaned every connection and terminal. Even pulled the battery switch thing off the bulkhead to check all the connections on the backside. Clean as can be.

What’s so frustrating is that it started just fine the day this all started. Fine going in the water, fine after we shut down a couple times to watch the dolphins. Then after sitting at the beach for a while she didn’t want to start up to go home. The battery or connections seem like they MUST be the issue, but so far everything just checks out. And the battery is very doubtfully the problem as the port engine cranks strong and fires up fairly quickly.

 

[Beachbummer]

Have you tried another battery? or while the battery is on the charger? just for grins, pretending the other starter is stringer/more powerful?

This is indeed a stumper. If you are turning the starter with jumper cables you have excluded all wiring from the boat, so that's not it.

 

[Kernel]

Have you tried another battery? or while the battery is on the charger? just for grins, pretending the other starter is stringer/more powerful?

This is indeed a stumper. If you are turning the starter with jumper cables you have excluded all wiring from the boat, so that's not it.

The only way to get it to start is while it’s on the charger with the charger providing an extra 50amps. The charger is three settings, slow charge 2amps, quick charge 10amps, and start boost 50amps. Even with the extra 50amps it takes in excess of 10 seconds of cranking to start it. Even then, it won’t start every time.

I’ve gone pretty far down the rabbit hole and calculated that given an estimated 4’ battery lead, 2 AWG copper wire with aluminum connectors, I should be seeing a 0.8v drop between the battery and the relay.

Voltage Drop Calculator

This free voltage drop calculator estimates the voltage drop of an electrical circuit based on the wire size, distance, and anticipated load current.

www.calculator.net

I’m getting 0.6-0.7v drop to BOTH relay inputs, leading me to believe that both leads are the same length. I initially thought that the starboard engine would have a longer lead (since it is further from the battery) and hence I’d see a greater drop, but that doesn’t seem to be the case. If it were, I suppose a case could be made that there should also be a greater amp drop on the longer lead.