LostPiker Posted March 21, 2023 Share Posted March 21, 2023 In the seemingly never ending saga of the engine on our boat, we took it out for the first launch on Saturday. Weather wasn't good but we just wanted to test the boat with the new engine so happy to just stick to sheltered waters around Calshot. Didn't start well when the engine wouldn't start but that was quickly diagnosed to me forgetting to put the kill cord on. Engine started, we push off the trailer and it died. Restarted poodled around while I parked, and that was it. Wouldn't rev mush over idle and kept cutting out. My boat mate who was on the boat managed to coax it to the jetty by the slip where we fiddled with the vessel view app and checked wiring etc to no avail. I tied a long line to the front and pulled it back around to the slip and back on the trailer. There are 2 faults in the app: 711-24 Oil level sensor - The input circuit for the sensor is above the valid limit. Oil level sensor in the tank is not working properly. Check oil level before continuing engine operation. 451-25 Pitot pressure - The input circuit for the sensor is below the valid limit. Pitot sensor is not working properly From a bit of googling the second one is probably because there isn't a pitot sensor on the engine and its just the first one that we need to worry about. Seems the floats in the tanks have a magnet on them that falls off and a new tank is £500, a new sensor is £45. Any one on here got experience of repairing the tank rather than replacing? Already spent far too much on this engine. Tempting to bypass the sensor but if we were to run out of oil and wreck the engine properly it would make the new tank seem cheap... Quote Link to comment Share on other sites More sharing options...
GPSguru Posted March 21, 2023 Share Posted March 21, 2023 2 hours ago, LostPiker said: In the seemingly never ending saga of the engine on our boat, we took it out for the first launch on Saturday. Weather wasn't good but we just wanted to test the boat with the new engine so happy to just stick to sheltered waters around Calshot. Didn't start well when the engine wouldn't start but that was quickly diagnosed to me forgetting to put the kill cord on. Engine started, we push off the trailer and it died. Restarted poodled around while I parked, and that was it. Wouldn't rev mush over idle and kept cutting out. My boat mate who was on the boat managed to coax it to the jetty by the slip where we fiddled with the vessel view app and checked wiring etc to no avail. I tied a long line to the front and pulled it back around to the slip and back on the trailer. There are 2 faults in the app: 711-24 Oil level sensor - The input circuit for the sensor is above the valid limit. Oil level sensor in the tank is not working properly. Check oil level before continuing engine operation. 451-25 Pitot pressure - The input circuit for the sensor is below the valid limit. Pitot sensor is not working properly From a bit of googling the second one is probably because there isn't a pitot sensor on the engine and its just the first one that we need to worry about. Seems the floats in the tanks have a magnet on them that falls off and a new tank is £500, a new sensor is £45. Any one on here got experience of repairing the tank rather than replacing? Already spent far too much on this engine. Tempting to bypass the sensor but if we were to run out of oil and wreck the engine properly it would make the new tank seem cheap... If the oil alarm is activated, the optimax goes into limp mode, which means it wont rev. Do you have an engine tank as well as a main tank, if yes, the you have to prime and bleed the engine tank. Just take the lid off and run the engine until the tank fills, then refit the cap. Quote Link to comment Share on other sites More sharing options...
GPSguru Posted March 21, 2023 Share Posted March 21, 2023 You can ( and a lot of users do) epoxy the magnet back onto the float. Not all the opti’s have the float switch, but a wiring fault gives the same alarm. Is your tank like this ? Quote Link to comment Share on other sites More sharing options...
LostPiker Posted March 21, 2023 Author Share Posted March 21, 2023 1 hour ago, GPSguru said: You can ( and a lot of users do) epoxy the magnet back onto the float. Not all the opti’s have the float switch, but a wiring fault gives the same alarm. Is your tank like this ? Unless I'm missing something I'm pretty sure we just have the engine tank. I had a look but to be honest I was so pissed off that it still didn't work I didn't look properly but how do you get in to the float to glue the magnet back on? Looked a bit like a ship in a bottle to me and would need an gynecologist to get to? Quote Link to comment Share on other sites More sharing options...
LostPiker Posted March 21, 2023 Author Share Posted March 21, 2023 1 hour ago, GPSguru said: You can ( and a lot of users do) epoxy the magnet back onto the float. Not all the opti’s have the float switch, but a wiring fault gives the same alarm. Is your tank like this ? can you link to where you got that image from? Quote Link to comment Share on other sites More sharing options...
Saintly Fish Posted March 21, 2023 Share Posted March 21, 2023 1 hour ago, LostPiker said: can you link to where you got that image from? Please LostPiker 1 Quote Link to comment Share on other sites More sharing options...
LostPiker Posted March 21, 2023 Author Share Posted March 21, 2023 17 minutes ago, Saintly Fish said: Please Lol. Sorry mum. Please GPS Andy135, Saintly Fish and GPSguru 1 2 Quote Link to comment Share on other sites More sharing options...
Saintly Fish Posted March 21, 2023 Share Posted March 21, 2023 15 minutes ago, LostPiker said: Lol. Sorry mum. Please GPS That's better. Good boy. Quote Link to comment Share on other sites More sharing options...
GPSguru Posted March 21, 2023 Share Posted March 21, 2023 3 hours ago, LostPiker said: can you link to where you got that image from? Yes, no problem, I will hopefully sort it out later this evening. Quote Link to comment Share on other sites More sharing options...
suzook12 Posted March 21, 2023 Share Posted March 21, 2023 Quote Link to comment Share on other sites More sharing options...
suzook12 Posted March 21, 2023 Share Posted March 21, 2023 As it says on the image, I use boats.net for referencing etc Quote Link to comment Share on other sites More sharing options...
suzook12 Posted March 21, 2023 Share Posted March 21, 2023 https://www.boats.net/catalog/mercury/outboard/90hp/90hp-dfi-1b736885-up/oil-tank-75-90-115-jet-80 Quote Link to comment Share on other sites More sharing options...
Dicky Posted March 21, 2023 Share Posted March 21, 2023 Are you sure it doesn't have a pitot sensor? have a you much experience of the Optimax, i would get a mariner/mercury mechanic to check it out Quote Link to comment Share on other sites More sharing options...
JDP Posted March 21, 2023 Share Posted March 21, 2023 (edited) When I had a piece of crap 90 merc two smoke, the oil chamber needed to full and the engine trimmed down fully. I had much the same issue where it cut out, so went through checking isolation switches etc etc but when I turned off the battery and back on with the engine key still in the on position, it burnt out the electrical rectifier (costing $500). With mine the oil reservoir needed to always be a minimum of 3/4 full . Soon replaced it with a Yam 4 stroke 70 which surprisingly gave much the same performance but without the high fuel use (once propped right). Edited March 21, 2023 by JDP LostPiker 1 Quote Link to comment Share on other sites More sharing options...
JDP Posted March 21, 2023 Share Posted March 21, 2023 (edited) 9 minutes ago, JonC said: That’s gonna cheer him up no end 🤣 It should do if its simply a case of keeping the oil topped up ahead of every trip instead of every three trips like I was trying. Once I found out, I could simply keep it filled and not have issues. The rectifier was a known issue is you did what I did and turn on the battery isolator while the engine was in the start position, if I had known before hand I possibly wouldn't of made the mistake. Also, it was simply a bit of a piss take on the merc, they are very good motors these days, I would happily buy another (already have a 75 merc 4 stroke which has been faultless). Edited March 21, 2023 by JDP Quote Link to comment Share on other sites More sharing options...
JDP Posted March 21, 2023 Share Posted March 21, 2023 (edited) 2 minutes ago, JonC said: Are these units too clever to be run pre mixed? I’ve had two strokes that had been hard wired so to speak, but they were a lot older. Ive done the same with older ones but was advised not to on the newer ones. I stay way from doing much to my outboards and leave it to the mechanic, who comes to my house to work on any engines I need looking at. The mechanic has a commercial boat that I often skipper, so looks after me well in terms of priority and price. Edited March 21, 2023 by JDP Quote Link to comment Share on other sites More sharing options...
GPSguru Posted March 21, 2023 Share Posted March 21, 2023 8 hours ago, LostPiker said: can you link to where you got that image from? Yes, it came from boats.net, and Suzook12 has kindly placed the link. The opti is actually a very good engine, and when running properly is also very reliable. The oil injection system is somewhat complex, put generally apart from the 'oil level' issue, give very little problems. The opti always had a reputation regarding the oil injection, as some used to just sip oil and others used to drink oil, but there seemed to be no reason for the difference and the usage and performance was similar. If you get the opportunity, it maybe wise, to have a marine grease monkey who is very familiar with the opti to take a look at it, as some of the fault symptoms and codes are not what they seem (a bit like cars). There are several thread on the USA site 'Hull Truth' that relate to your issues, but be warned, Hull Truth can be quite toxic at times, but equally a good source of info from a good number of folk that know what they are talking about. Quote Link to comment Share on other sites More sharing options...
LostPiker Posted March 24, 2023 Author Share Posted March 24, 2023 On 3/21/2023 at 10:52 PM, GPSguru said: Yes, it came from boats.net, and Suzook12 has kindly placed the link. The opti is actually a very good engine, and when running properly is also very reliable. The oil injection system is somewhat complex, put generally apart from the 'oil level' issue, give very little problems. The opti always had a reputation regarding the oil injection, as some used to just sip oil and others used to drink oil, but there seemed to be no reason for the difference and the usage and performance was similar. If you get the opportunity, it maybe wise, to have a marine grease monkey who is very familiar with the opti to take a look at it, as some of the fault symptoms and codes are not what they seem (a bit like cars). There are several thread on the USA site 'Hull Truth' that relate to your issues, but be warned, Hull Truth can be quite toxic at times, but equally a good source of info from a good number of folk that know what they are talking about. Thanks. I had Barry at Winsor Marine service it, and have the shift rod straightened already. As I'm already £2k into a supposedly good engine I think I'll bypass the sensor and take it for a trial before I spend any more on it Quote Link to comment Share on other sites More sharing options...
GPSguru Posted March 24, 2023 Share Posted March 24, 2023 4 hours ago, LostPiker said: As I'm already £2k into a supposedly good engine I think I'll bypass the sensor and take it for a trial before I spend any more on it Good plan, but remember to check the oil level every trip. suzook12 1 Quote Link to comment Share on other sites More sharing options...
LostPiker Posted August 23, 2023 Author Share Posted August 23, 2023 Little update, it gets worse. I think I managed to buy the worst outboard available in the UK. Tried to bypass the sensor and it still didn't work, bought a new sensor and tried to trick it with a magnet. No change so I gave in and took it to a Mercury dealer. Some good news is the tank is fine, the float was held down by sludge which when cleaned works perfectly and no oil errors and the compression is fine. Almost nothing else is though. All 3 fuel pumps either need rebuilding or replacing Alternator mounts perished Throttle not opening fully throttle body linkage seized Battery undersized Engine harness cut into and damaged Air filter very old and damaged fuel filter damaged Another £2k bill to put it right🥺 by the time its back in the water will have spent what I could have got a brand new engine for. Painful and expensive lesson learn Andy135 1 Quote Link to comment Share on other sites More sharing options...
Saintly Fish Posted August 23, 2023 Share Posted August 23, 2023 1 hour ago, LostPiker said: Little update, it gets worse. I think I managed to buy the worst outboard available in the UK. Tried to bypass the sensor and it still didn't work, bought a new sensor and tried to trick it with a magnet. No change so I gave in and took it to a Mercury dealer. Some good news is the tank is fine, the float was held down by sludge which when cleaned works perfectly and no oil errors and the compression is fine. Almost nothing else is though. All 3 fuel pumps either need rebuilding or replacing Alternator mounts perished Throttle not opening fully throttle body linkage seized Battery undersized Engine harness cut into and damaged Air filter very old and damaged fuel filter damaged Another £2k bill to put it right🥺 by the time its back in the water will have spent what I could have got a brand new engine for. Painful and expensive lesson learn Then I hope you are going to put the money toward a new one and not waste any more time on this one!! Quote Link to comment Share on other sites More sharing options...
suzook12 Posted August 24, 2023 Share Posted August 24, 2023 15 hours ago, LostPiker said: Little update, it gets worse. I think I managed to buy the worst outboard available in the UK. Tried to bypass the sensor and it still didn't work, bought a new sensor and tried to trick it with a magnet. No change so I gave in and took it to a Mercury dealer. Some good news is the tank is fine, the float was held down by sludge which when cleaned works perfectly and no oil errors and the compression is fine. Almost nothing else is though. All 3 fuel pumps either need rebuilding or replacing Alternator mounts perished Throttle not opening fully throttle body linkage seized Battery undersized Engine harness cut into and damaged Air filter very old and damaged fuel filter damaged Another £2k bill to put it right🥺 by the time its back in the water will have spent what I could have got a brand new engine for. Painful and expensive lesson learn Doesn't sound all that bad. Battery is nonsense, If it cold starts with ease, it's big enough, Throttle body linkage will be why throttle isn't opening fully. Alternator mounts, again, no biggy, fuel and air filters regular service items. So just leaves the pumps, not sure what the deal is on optimax, and no doubt they are quoting to replace the entire engine loom? Looms can be repaired quite easily but I can understand you may well want a new one anyway. But there's plenty there you can do yourself to take a lump off of the £2k bill. If you bought this from a dealer I would be going back to them and having it out with them though..... Quote Link to comment Share on other sites More sharing options...
LostPiker Posted August 24, 2023 Author Share Posted August 24, 2023 4 hours ago, suzook12 said: Doesn't sound all that bad. Battery is nonsense, If it cold starts with ease, it's big enough, Throttle body linkage will be why throttle isn't opening fully. Alternator mounts, again, no biggy, fuel and air filters regular service items. So just leaves the pumps, not sure what the deal is on optimax, and no doubt they are quoting to replace the entire engine loom? Looms can be repaired quite easily but I can understand you may well want a new one anyway. But there's plenty there you can do yourself to take a lump off of the £2k bill. If you bought this from a dealer I would be going back to them and having it out with them though..... re battery, thats my thoughts on it. No idea why a 1500cc outboard would need a battery bigger than a 2.5l diesel car? Loom isn't being replaced, it works just been cut into and rejoined and don't look great but it works so it stays. One of the fuel pumps - the lift pump can be rebuilt so they are doing that, the other 2, low pressure and high pressure apparently can't be so are being replaced. I normally do everything myself, I've rebuilt car engines etc in the past but I just want to use the boat and I don't know enough about boat engines to be confident yet, I didn't know this engine had 3 fuel pumps to go wrong for example. It was tempting to put the money towards a new engine on finance and give up on this one but the other money is gone and isn't coming back so its a choice of spending 2k or spending 8k minus what we'll get back on a spares or repair outboard. It'll all be forgotten when we get out on the boat and have a beer and catch a few fish Andy135, Geoff and suzook12 3 Quote Link to comment Share on other sites More sharing options...
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