2005 Islandia Optimax 250 will not start

[75sausage]

Hi, I just bought a 2005 Islandia Optimax 250 which will not start on its own.

The boat was bought at an auction so there isn't much in terms of history from the previous owner. The two noticeable things that give clues are: registration dating back to 2010, and an oily residue covering the bottom half of the engine bay/bilge likely from some kind of partial submersion.

The engine cranks but will not start. I can get the boat started by using starting fluid (OH NOES! I swear I didn't know before today that is a no-no and I am hoping I didn't cause any permanent damage). The other method that I got the boat started was to crank it until I heard some ignition then quickly throw it into Forward gear and apply more throttle. Once started the engine seems to be running fairly smoothly.

What I have done to try and mitigate the problem:

• drained/siphoned the gas out of the tank and replaced with new gas (treated with Stabil marine stabilizer) checking the pick up screen for any obstructions
• drained the vapor separator
• replaced inline fuel filter at the pick up pump
• replaced fuel water separator adding the recommended mixture of 2 cycle oil, and Quicksilver fuel additives as listed in Service Manual.
• checked fuses
• replaced spark plugs with factory recommended NGK ones (the existing ones where a mixed bag of autolite and ngk)
• replaced air filter (mounted in air intake housing)

Admittedly I have not done a lot of searching for possible culprits. But I was going to check cylinder compression and fuel pick up pump vaccum and pressure next.

The Factory Service manual also suggests checking voltage while cranking (should be above 8VDC), checking air pressure at cranking.

I'll take any and all suggestions on the appropriate course of action to get it to start.

 

[Dr Honda]

Adding oil to the main fuel tank won't help your engine. It's direct injected... so that oil never sees anything other than the top end. Did the opti manual say to do that, or was it a generic merc manual?


Yes... the air, or fuel pressure could be low, and it needs to be checked.

When the engine is running... what is the top RPM? What is the idle RPM?

 

[75sausage]

Oh, I didn't add oil to the fuel tank. I added it to the fuel water separator filter. The "mixture" is in the opti manual as a winterizing action. Mix:

(1.) 0.68 oz (20 cc) or 2 tablespoons of Premium Plus Outboard oil or Optimax/DFI
2-Cycle Outboard Oil.
(2.) 0.27 oz (8 cc) or 2 teaspoons of Quickleen lubricant.
(3.) 0.27 oz (8 cc) or 2 teaspoons of Fuel System Treatment & Stabilizer.
d. Pour this mixture in the new water separator fuel filter.

The Idle RPM is 1000
The WOT I'll have to re-check.

 

[Dr Honda]

If you are idling at 1000 RPM's... then that's about right.


Have you tried to just turn the wheel to one side? It will bump the idle a little.


After checking the air, and fuel pressure... I would also check the TPS.


Just for giggles... you may want to check the compression. When it drops... you get hard starting... especially when in the water.

 

[Carlangas1989]

Wrong post sorry

 

[75sausage]

My boat has been in the shop for the past month. The mechanic found a sticking flutter valve on the high pressure fuel pump. He repleced the pump but the didn't fix the problem fully. He says that the engine now starts but does not run right due to air bubbles in the fuel, and he isn't sure what is causing it.
Sigh.

 

[75sausage]

Double post.

 

[Dr Honda]

How does he know there is air in the fuel? None of the hoses are clear. SO... if he found air... then he should move down the system, and find where it's clean. Then... that will point out where the leak is happening.

AND... if the mechanic said "Flutter Valve"... then he's a moron.


I'm thinking he's feeding you a load of crap, and just doesn't want to work on it.


If he is a legit Mercury mechanic... then he should have a DDT, and he can read out all the info live, and he will see what's wrong.



Let em ask you this... once it's started... will it come back to an idle? (in the water) If it does... will it run smooth after?

 

[75sausage]

I found this Marina on the Mercury web site listed in the Master Technician listings. The guy did replace the fuel pump; I saw it out of the boat. I am unsure about the diagnostic tools or skill but I will surely ask him about the DDT and how he determined that there are air bubbles in the fuel. I will also get details about how it runs.
In truth the information above didn't come directly from the mechanic.

 

[Dr Honda]

OK...

I didn't mean to come off harsh in my post above... but we get a bunch of reports here of tech's who do everything half ass'ed. And, in turn... cost the owners more money by changing parts that didn't need to be.


For air to get into the fuel lines... it would have to be on a suction side. SO... that would be the hose from the tank, to the lift pump. After the lift pump, it's under pressure... so a leak would squirt out. (a master tech should know that)


But... as I asked before... once it's started... will it come back to an idle? (in the water) If it does... will it run smooth after?

 

[75sausage]

The mechanic was able to get the boat running. Ultimately, the following parts were replaced:
1. High pressure fuel pump (the little needle on the outflow was sticking at times)
2. Tracker valve
3. Air pump reed plate (one of the reeds was busted)
The engine now starts without fail and runs fairly smoothly. I had it at Raystown Lake in PA for the whole past week and ran it on 4 separate days. The only issue the I uncovered was that it appears the alternator is not working. I got a low battery alert as soon as I got the boat in the water. I kept the boat running by charging the battery overnight and running on battery, which would give me about 2 hours of running before the low batt. alarm would beep.

After using it on the water I have some concerns which I am hoping someone with an Islandia can speak to.

• The engine revs to a smidgen above 5000 rpm at full throttle: Is this an appropriate full throttle rev count?
• What kind of performance should I expect from this boat? With 3 adults on boat (700lb) I was able to get up to 28mph. With 4 adults and 4 kids it proved difficult to plane the hull (it took over 2 minutes) and after going on plane the boat only ran at 23 mph. Towing a tube makes things even slower and at times impossible to plane with the wrong weight distribution.
• The exhaust gasses are pretty pungent and, in my view, and make any kind of skiing activity unsafe. I also see some blueish smoke when running at full tilt.
• The engine is very thirsty, I used up a full tank after approximately 5 hours of use. I have a 50 gal tank. I did run the engine at full throttle most of the time due to sub par performance.
• At partial throttle, the engine stutters as if it is misfiring or loosing fuel pressure.

Instincts tell me I should take the lower unit apart and inspect the propulsion system for damage and wear as the most likely culprit of poor performance. Not sure how to diagnose the strong exhaust smell.

 

[75sausage]

I just found a problem which may be causing some of my issues. The drive belt tensioner is so lose that I can deflect it with my hands and there is a bunch of rubber dust covering the alternator and surrounding area.

 

[Dr Honda]

I just found a problem which may be causing some of my issues. The drive belt tensioner is so lose that I can deflect it with my hands and there is a bunch of rubber dust covering the alternator and surrounding area.

GEEEZZZZZ !!!!! another screw-up from the tech who gave you a BS answer about "Air in the fuel". On the 250 Opti engine... the air pump is run from that belt... so if it was loose, and there is rubber... just replace it. If it breaks... you will be dead in the water. (can't run without the air pump)


From your post #11.


If he found a broken reed in the air pump... I guarantee that was the problem. BUT... since I have a feeling this guy really didn't know what he was doing... you got a new fuel pump for no real reason. (and got charged for it)


Now... as far as the low speed, and no charging... yes... it could have been from the belt. But... on your engine... there should be a couple fuses. One of them is for the charging. (I'll have to look up what one it is)


To answer your questions directly:

1) They brought the top RPM's down on the 250. The limiter is at 5850 RPM's. So... peak RPM's should be right at 5600~5700. (the 240EFI ran way up at 6200)

2) My 240EFI Islandia will run 40 MPH all day long with 5~6 people, and the top up. If I'm by myself, with mimimum stuff, half tank of fuel, and the top back... I can just see 50 mph. Also... there should be minimal cavitation, and if I'm balanced... I'm up on step, and moving in 4~6 seconds. (or there about) Yesterday.... we had 40 mph on the GPS, and I was only up to about 70% throttle.

With that said... the pump makes thrust a little different than a prop. 5000 RPM is only 28 mph... but 6000 is mid to upper 40's. So... eventhough you are ~600 rpms low... that where all your top speed is.


3) The fumes should clear up once you get a full shot of air. If they don't... we can look into that deeper.

4) I'm not sure what the 250 engine will drink... but my 240 EFI will burn almost 27 gal/hr at full throttle. (it's going to be close) But once you find your lost power.... you will get up to speed and be able to pull back. At 75% power... the fuel consumption will drop in half. (or there about)

5) Close... I think it's low air pressure from the belt.



Anyway... fix the belt... and we will go from there.

 

[Dr Honda]

On the starboard side of the engine... there is a fuse block. Open the cover, and check it. Also... there is a fusable link for the alternator, next to the fuse block. It can be burnt.

 

[75sausage]

You hit the nail on the head. The fusible link is burnt on the positive lead between the alternator and the starter solenoid. The service manual does not show it very clearly but I found it.

 

[75sausage]

Parts are on the way... can't wait to put it back together to test.

 

[75sausage]

I installed the fusible link lead and a new $100 alternator. My meter is only reading the battery level of voltage not the approx. 14.0 V that I was expecting. Fuses rechecked so everything seems ok but no charge. Hmmm...

 

[75sausage]

Ok, I swapped the old alternator back in and cleaned the starter connections, to see if this makes any difference. No good. At the starter output terminal I get 12.14V with engine running and 12.41V with engine off. I tried to follow the service manual diagram for alternator wiring to trace the depicted 20A fuse but could not find it.

The only fuses I found are the ones below.

 

[Dr Honda]

I just noticed that you said it wasn't charging.

Let me dig though the manual, and I'll get back to you.

 

[Dr Honda]

I don't like the 250 manual. There isn't a full wireing diagram.


Anyway... in the top picture... the 20a fuse is the "Accessories" fuse in the bottom picture.


The wire that controls the field (I think) is the purple wire. It should be coming up from the key. SO... unplug it from the alternator, and check it for 12v with the key on. If there isn't any power on it... then the alternator won't start up.

 

[75sausage]

I checked before reading your latest post but with the Engine Running I was getting 12.17V and with Engine Off (I assume key off) it was reading 2.8mV at the purple wire. I assume that Engine On is synonymous with Key On.

The accessories fuse is good.

I did more checks with both my original alternator and a replacement chop'o one and was getting the same results. Pretty much I get battery voltage readings at most test points with engine running:

Alternator output
Purple wire in alternator harness plug
Red wire in alternator harness plug
... all read 12.12 and falling. The battery voltage at the same test points with the engine stopped jumps up to 12.50v approx.
Resistance between alternator body and engine block at alternator ground end points is 7ohms +/- 3ohm.

I also pulled the positive terminal off the battery with engine running which killed the motor with both the old and the replacement alt.

Could the battery cause these symptoms. It's a 850 MCA battery which appears to function and hold the charge just fine. It starts the motor without hesitation and I can run for an hour before the low battery alarm sounds. It has been siting for the past 2 weeks and I haven't noticed any voltage drop.

Do you think that the relay plays a role in the alternator circuit?

 

[Dr Honda]

First... NEVER pull the power from the battery when the engine is running. The resulting (potential) power spike can kill the engine computer, or roast the alternator. Not to mention... most engines need the battery in place to complete the circuit. Pulling the power to check alternator output is a VERY old test, going back into the 50's, when cars went from having "Generators" to "Alternators". (Way before digital electronics) Before that... it was used to "Polarize" generators. (When some cars had a positive ground system)

If you have 12v on the purple wire with the key on.... and the fuse is good.... and the fusible link is good.... then I'd say your replacement alternator is bad. You can take it to most auto parts stores... and they have a machine to test alternator outputs.



As far as the battery... it sounds like it's fine.

 

[75sausage]

I knew it was a bad idea... must be getting desperate :facepalm:

I'll get the alternators checked.

 

[75sausage]

I got both alternators checked and both were bad. So... I returned the new one that I got online and the alternator guy hooked me up with a replacement for $150. Installed the replacement along with new tensioner spring and belt.
13.75V healthy charge at idle. I am very excited. Now I have to take it out and check the performance.