Mike Nolan Posted May 16, 2017 Share Posted May 16, 2017 Hi All, I’m having issues with my outboard losing power as I increase the speed. It’s a 30hp Evinrude, most likely a 1995/96 model (not sure of the exact model). Starting the engine, idling, and running a low speeds it has no issue. It’s when I start to increase the speed that it starts to lose power and rev quite erratically. As soon as I pull back the throttle it runs fine. I’ve uploaded a few videos onto youtube of the issue occurring as I increase the speed. https://www.youtube.com/watch?v=0Lwf96CGgoA https://www.youtube.com/watch?v=6alON8wwqIU I got the boat in January, and had a similar issue a few weeks after buying it. That issue turned out to be fuel starvation due to a leak in the fuel pump. After a service, new fuel pump, and $750, the boat ran great for 2-3 months. I use by boat quite regularly, so it probably had about 20-30 issue free trips before it started occurring again. Given the previous issue and advice I’ve read online, I suspected this was also a result of fuel starvation. I’ve done the following checks on the fuel system: Checked the fuel line is pumping through plenty of fuel (fuel line was replaced in January) Loosened the screw on the fuel pump, and pumped the primer bulb. Plenty of fuel comes through Removed the screw at the bottom of the fuel bowl, then pumped the primer bulb. Penalty of fuel comes through I’ve also visually inspected all of the hoses from the fuel line connection, through to the fuel pump, and through to the carburettor, all of which appear to be in good condition with no signs of leaks or loose connections Through all of these checks I can’t find any issue. I’ve tried using different fuel and had the same result. I’m also very precise when mixing in the 2-stroke outboard oil. When the boat was serviced in January, the spark plugs we’re replaced and the mechanic was impressed with how good the compression was considering the engine’s age. My next thought it to take out and clean the carburettor, however I’m reluctant to do so before I get more advise on the matter. Any suggestions or advice that anyone has would be greatly appreciated. If you need any more details please let me know. Thank you! Link to comment Share on other sites More sharing options...
jeffb5.8 Posted May 16, 2017 Share Posted May 16, 2017 I think you have pretty much all items I would suggest covered. After watching the video I think it's a spark issue more than a fuel issue, fuel will just die, spark will cause it to jitter like it did. 1. Re check spark plugs, gap and condition 2. Running it at night without a cover and see if the spark plug leads are arcing to part of the block, 3. Check the coils for signs of damage or the white marks from Arcing. Link to comment Share on other sites More sharing options...
Mike Nolan Posted May 16, 2017 Author Share Posted May 16, 2017 Thanks for the suggestions Jeff. I'll give them a try Regards, Mike Link to comment Share on other sites More sharing options...
Nolongeramember Posted May 16, 2017 Share Posted May 16, 2017 Might be an obvious question but does it have the problem when it's actually in gear with the propellor turning? I'm asking because my engine sounds exactly like yours in the clip when I lift the accelerator lever. Its just a rev limiter. When you actually put it in gear and rev it, it revs all the way. Link to comment Share on other sites More sharing options...
Nolongeramember Posted May 16, 2017 Share Posted May 16, 2017 And be very very careful putting in gear and turning the propellor when testing if you do. Make sure no one or anything is anywhere near the prop! Link to comment Share on other sites More sharing options...
rickmarlin62 Posted May 16, 2017 Share Posted May 16, 2017 pull your carbies off take bowl off and clean out gunk build up in there you will have crap in there blocking main jet when the flow increases when you back off they drop back to bottom of bowl..had same trouble with my 60yammie took all three carbs off cleaned them put water separator filter on and havnt prob since...unleaded fuel leaves deposits when it dries out...just use some carby cleaner and spray thru the ports in your carbs while apart..rick Link to comment Share on other sites More sharing options...
Mike Nolan Posted May 16, 2017 Author Share Posted May 16, 2017 10 hours ago, Roylo said: Might be an obvious question but does it have the problem when it's actually in gear with the propellor turning? I'm asking because my engine sounds exactly like yours in the clip when I lift the accelerator lever. Its just a rev limiter. When you actually put it in gear and rev it, it revs all the way. Hi Roylo, When I first put it in gear and the prop is turning there are no issues. If I continue to run it at a low speed there are still no issues. It's only when the speed is increased that the issue starts occurring. Link to comment Share on other sites More sharing options...
Fishop Posted May 18, 2017 Share Posted May 18, 2017 Had similar issues a few months back. Changed fuel filter (was dark brown - new one was white) and also the water separator filter while I was at it. Fixed the prob havnt had an issue since. Link to comment Share on other sites More sharing options...
Mike Nolan Posted May 18, 2017 Author Share Posted May 18, 2017 (edited) On 5/16/2017 at 9:48 PM, jeffb5.8 said: I think you have pretty much all items I would suggest covered. After watching the video I think it's a spark issue more than a fuel issue, fuel will just die, spark will cause it to jitter like it did. 1. Re check spark plugs, gap and condition 2. Running it at night without a cover and see if the spark plug leads are arcing to part of the block, 3. Check the coils for signs of damage or the white marks from Arcing. Hi Jeff, I took your advice and looked into the spark. - Pressure Test: got 97 PSI on the top cylinder, and 100 on the bottom - Spark Plug Gap: .04" and .038" - Spark Plug Condition: Look ok (see attached photos) - Spark Test: the top coil seems to be sparking well, however the bottom coil isn't. Below are links to videos of the spark test. Not until the 3rd crank did the bottom coil spark. Top: https://www.youtube.com/watch?v=Nw2b0-V8wf8 Bottom: https://www.youtube.com/watch?v=6p7yNVXI_DM - Condition of Coils: the top coil looks ok, but the bottom coil is looking pretty worn. (see attached photos) Given the condition of the bottom coil, and how poorly it's sparking I think this is my issue. What are your thoughts? Bottom Coil Top Coil Edited May 18, 2017 by Mike Nolan Link to comment Share on other sites More sharing options...
jeffb5.8 Posted May 18, 2017 Share Posted May 18, 2017 (edited) That coil does seem like it's seen better days. maybe give the coil a clean up and clean the plugs and see if that helps or if you can find a new or good 2nd hand unit to try. the top and bottom coil should be the same. i have wrapped a coil with electrical tape in dodgy spots to get it to hold together and stop arching and get me home it also confirmed the coil was on its way out. Edited May 24, 2017 by jeffb5.8 Link to comment Share on other sites More sharing options...
JohnDory Posted May 19, 2017 Share Posted May 19, 2017 As rick said it sounds like fuel issues! TLC to your carbies + filters and some new plugs would good start JD Link to comment Share on other sites More sharing options...
recurve Posted May 24, 2017 Share Posted May 24, 2017 I had this type of issue but only under load with a 140 Yamaha V4 2 stroke. Everyone said it was fuel so pulled the carbs apart then they said it was spark plugs and cables so replaced all of those. Then everyone said it was gunk. In the end it that the chambers were corroded and it was not getting cool enough. The alarm should have sounded but the guy who installed it did not hook up the alarm. Fix was to permanently open the thermostat. Just another lead for you to try. Was the same as what your getting. Idle no problem, put the gas on and it dropped away. Good Luck......in the end I replaced the engine. Lost confidence with it. Link to comment Share on other sites More sharing options...
jeffb5.8 Posted May 28, 2017 Share Posted May 28, 2017 Hi Mike how did you go with the motor any resolution? Link to comment Share on other sites More sharing options...
Mike Nolan Posted June 13, 2017 Author Share Posted June 13, 2017 Hi Jeff, Sorry for the late response, I've been away for the past 2 weeks. I took the carby off, gave it a thorough clean with carby cleaner and compressed air. I also got a carby kit, and replaced a few of the small parts. When I put the carby back on and went to test it, I noticed fuel is coming out of the top of the carby when I pump the primer bulb. I suspect there is an issue with the float and/or needle, so it's not sealing off the fuel bowl as it should when it gets full. I tried starting the engine, and no luck. Sounds like its flooded (probably due to the bowl overflowing). I'm going to take the carby back out this weekend and have a look at the float and needle. Might even put the old float and needle back in and see out it goes. I've also bought 2 new coils to replace the old ones which are looking pretty sore and sorry. I'll wait till I've fixed the carby issue before I tackle that though. Regards, Mike Link to comment Share on other sites More sharing options...
Mike Nolan Posted June 13, 2017 Author Share Posted June 13, 2017 I should mention I also put new spark plugs in. At $5 each I thought it couldn't hurt to replace them. Link to comment Share on other sites More sharing options...
jeffb5.8 Posted June 13, 2017 Share Posted June 13, 2017 Nice sounds like your on the right track and will be back in the water soon. keep us informed Link to comment Share on other sites More sharing options...
Geoff Posted June 13, 2017 Share Posted June 13, 2017 This is way out in left field but some motors have a device in the block that if the motor overheats it cuts the throttle back to avoid damage . These can become faulty over time even if the temp is ok if yr motor has one , perhaps worth checking Link to comment Share on other sites More sharing options...
recurve Posted June 14, 2017 Share Posted June 14, 2017 That's what happened to my old motor 1994 Yamaha V4 140 . The throttle cut right back but the overheat alarm was not going off. Had everyone in a spin. Finally found a part time mobile mechanic who worked it out in 30 min and charged me a couple of Hundred. Had been to three big shop Outboard places and wasted money and time with no results and all sorts of wild diagnostics, Link to comment Share on other sites More sharing options...
Mike Nolan Posted June 16, 2017 Author Share Posted June 16, 2017 Hi All, I took the carby back out, and removed the new float and needle that I had put in. I replaced with the old float and needle, and that fixed the issue with fuel coming out of the top of the carby. I started it up, and it ran pretty well at lower speeds, but then misfired as I increased the throttle. It felt like it was getting up to a higher speed before misfiring, but still misfiring nonetheless. I then put in the new spark plugs, tested it, and again it was misfiring. Lastly, I put on the new coils, and finally success! I slowly increased the throttle till it was almost at full throttle, then let it run for a few minutes. I did this twice more, and it didn't misfire at all. Jeff was right from the start, it was a spark problem not the fuel. I did however notice another issue. There is a brown sludge coming out of one of the holes that water comes of. When the engine is running water is coming through, but when I stop the engine, the brown sludge starts to come out. I have a feeling it may be mud, as it didn't feel or smell like grease. Also, when the boat is tied to my jetty it sits on the mud at low tide. Anyone have any alternative ideas or suggestions about this? Lastly, thank you to everyone that has given me advice. Your help is greatly appreciated. Regards, Mike Link to comment Share on other sites More sharing options...
raging Posted June 16, 2017 Share Posted June 16, 2017 Nice one. is that mud or gearbox oil ? Link to comment Share on other sites More sharing options...
Mike Nolan Posted June 16, 2017 Author Share Posted June 16, 2017 Just now, raging said: Nice one. is that mud or gearbox oil ? It doesn't feel or smell like gearbox oil (not that I'm an expert on gearbox oil) Link to comment Share on other sites More sharing options...
jeffb5.8 Posted June 16, 2017 Share Posted June 16, 2017 Easy way to check if it's gearbox fluid is to undo the bottom drain plug just a little until some gearbox fluid comes out. If it looks like mud then you have answerd your question. Which means you may have a gearbox seal issue. if it's clean and Oil looking then you may have mud in you water jackets. which would require removing the thermostat housing and thermostat and flushing the cooling system.some pipe cleaners used to unblock drain holes Might be time to change the gearbox fluid if it hasn't been changed in a while. Do you know when it and the water pump impeller was changed? Link to comment Share on other sites More sharing options...
sydney south Posted June 17, 2017 Share Posted June 17, 2017 Looks like oil sludge to me. Link to comment Share on other sites More sharing options...
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