Help Evinrude 35Hp Still one cylinder

My 35HP Evinrude 1984 lost one cylinder on last trip of year, after 1/2 Hrs slow sailing, as a sudden stroke. I pulled flywheel as it seemed as magnetos touched a coil - corrected. Checked ignition and changed plugs - ok both sparks can jump 1/2" gap. Cleaned carb. Compression 122 on both cyls, cold motor. It doesnt run at all on the one cylinder !!!! Why ? Can a ring be broken, and motor still have same compression ? The only hint i can give is when crancked slowly by hand, both cylinders do not give same intake sound ?? Can it be an airleak ?? When turned slowly it feels like the one cylinder have weaker compression or doesnt hold pressure as long. But gauge mesures exactly same pressure, 122 on both. I even tested gauge on another motor, but it is ok. Whan can be wrong. I strated on earmuffs and rev it up, but still only one cylinder.

Re: Help Evinrude 35Hp Still one cylinder

HI, Do you know which cylinder you are losing? The fuel pump is operated off one cylinder, if the fuel pump diaphram leaks, it can internally sent fuel to that cylinder causing it to flood.

Re: Help Evinrude 35Hp Still one cylinder

ICEMANN thanks for reply.<br /><br />No I do not know which cylinder is missing. After attemt to repair, i only tested on earmuffs. Will flooding cause the cylinder not to fire at all, even when i rev it up on earmuffs, in gear ? I can test tomorrow, it is very late here now.

Re: Help Evinrude 35Hp Still one cylinder

Can you run it in a tank of water (trash can)?? If so, try the old cylinder drop test - You'll need a pair of INSULATED pliers. With the engine running, twist and remove one spark plug lead, there should be a noticable rpm drop (the engine may even stall). Re-install the lead and remove the other. Which ever lead has no change is the cylinder that isn't working. <br /><br />You noted a compression test, can you do a leak down test?? Is this the same 35 you were recently rebuilding??<br /><br />-John

Re: Help Evinrude 35Hp Still one cylinder

Hi G Dane<br />To determine which cylinder, pull off a plug wire and ground it. Do this one at a time and see which cylinder will run by itself.<br />Once you have determined this, do a spark test on the dead cylinder with engine running. Use a spark tester or old plug with widened gap grounded to block. The ignition for that cylinder may be weak while running. <br />By what you describe, it could also be a reed issue, but check the easy stuff first...<br />

Re: Help Evinrude 35Hp Still one cylinder

One other thing to check for (seeing as how compression reads good) is debris in the intake manifold. Had a motor once that sucked in part of the foam hood insulation that had decayed and got it wedged between a reed and the manifold plate. You mentioned the different sounds emminating from the carb - might be a cause...<br />- Scott

Re: Help Evinrude 35Hp Still one cylinder

Howdy, G Dane.<br /><br />Sure sounds like a reed problem to me. Could be bent, broken or merely chipped. <br /><br />With good compression, good spark and apparently good fuel mix it is the prime suspect. It will cause that cylinder to not run at all.<br /><br />Less likely, but possible is a blown crank seal. The engine will usually run, but poorly if a seal is blown.<br /><br />Let us know what you find.<br /><br />Red sky at night. . .<br />JB

Re: Help Evinrude 35Hp Still one cylinder

Thanks for all your replies<br /><br />I did a spark test with 1/2" gap, both sparks jumped bright, without missing. The upper lookes a bit weaker than the lower, but both jumped without missing, even beyound 1/2" on rope start.<br /><br />This is the 35 i rebuild 2 yrs ago. The error came up in a second -just like this.<br />I will do some further testing tomorrow. The reeds or a cranckseal could sound as possible reasons. The cylinder is totally dead, ist only running on one, no matter rpm. I gues fuel pump dia error would make it ignite at higher rpm. I will let you know.

Re: Help Evinrude 35Hp Still one cylinder

John - i dont have anything to do a leakdown test. If the one cylinder looses compression faster than the other - could it be a broken ring ?? Would it still have same compression if top ring is OK ?

Re: Help Evinrude 35Hp Still one cylinder

In a 2-stroke outboard, a compression test only tells you what is going on above the top ring when the ports are closed. A bad ring (or rings), scoring/scuffing, or a bad head gasket will not let the engine develop full compression - the compression test will show low if any of these are at fault. As you know the engine needs compression (in the combustion chamber), correct fuel/air ratio, correctly timed spark and the ability to exhaust in order to run.<br /><br />What a compression test doesn't tell you is what is going on in the crankcase, and below the lower ring. If the piston skirts are worn, or the lower ring is stuck in the piston groove, when the piston comes down in the cylinder bore it can't compress the fuel/air mix in the crankcase because the pressure "leaks down" by the lower ring (or piston skirt) and leaks out the exhaust port.<br /><br />Although there is no "text-book" test to check crankcase pressure, a leak down test can clue you into problems a compression test won't reveal.<br /><br />For example, another tech I know was having a problem wilth a 200 horse recently. Compression numbers weren't real high, but something we would all consider good. After repairing several existing problems, the engine still wouldn't run well. For what-ever reason he finally decided to do a leak-down test and found one cylinder leaking down 50% and another 90%. 35 to 40 percent is the max acceptable leak-down. In his case it was a ring in one cylinder and piston skirt in the other.<br /><br />If you have a crankcase seal or gasket leak, you can find it by running the engine and spraying all the crankcase seams, intake manifold etcetera with some engine tuner or fogging oil. As the gapped is momentarily "filled", you'll hear the engine running characteristic change.<br /><br />Keep "talking" with us, we'll bounce some more ideas your way...<br /><br />-John

Re: Help Evinrude 35Hp Still one cylinder

Now i had time to work on it again.<br /><br />It is the upper cylinder not running, for sure.<br /><br />Spark is bright blue and stable on both. Rechecked compression, exactly 122 on both.<br /><br />I tried to run it on earmuffs, only 1 minute, as it was onecylinder. I just changed sparkplugs before. Now the lower plug is a little big black. the upper is clean - it could look as there was i bit of WATER on it ?? When i put it back for winther, both plugs were black - a little oily. Will a blown headgasket make it miss totally on the one cylinder, even if compression is still 122 ?. Can a lower ring be broken, and compression still be ok ? I am just at the piont where i have to dissasemble. Can you give me any ideas. By the way - i ordered some gaskets and parts from theshadconnection - but they dont answer my mails. Do they exist anymore ? Is there another place to buy gaskets, impellers and so on at reasonable prices online, parts are pricey here. ?

Re: Help Evinrude 35Hp Still one cylinder

I have to ask you another question :<br /><br />Why should the headgasket blow, 30 hrs after rebuild and new block ? It ran like new till then.

Re: Help Evinrude 35Hp Still one cylinder

Howdy, GDane.<br /><br />You didn't say if you checked the reeds.<br /><br />A blown head gasket would not allow the compression numbers you got.<br /><br />Red sky at night. . .<br />JB

Re: Help Evinrude 35Hp Still one cylinder

I havnt checked the reeds yet - i will have to remove the carb and intake plate then.<br /><br />Ill be back

Re: Help Evinrude 35Hp Still one cylinder

JB you were perfectly right.<br /><br />Pulled carb 5 min ago. 1 reed leaf is missing.<br />I tried to find it with a light but no sign of it. One blade on other cylinder is cracked and missing a very little piece. Why is that ? Does anyone have a good idea to find the leaf - or do i have to disassemble.<br /><br />I have another readplate in stock.

Re: Help Evinrude 35Hp Still one cylinder

Can a broken leaf pass a cylinder while running ??<br /><br />What is the wisest to do now ??

Re: Help Evinrude 35Hp Still one cylinder

BUMP

Re: Help Evinrude 35Hp Still one cylinder

Great Dane<br />You MUST find the pieces of that reed leaf even if it means pulling the engine apart.Dont just look for the leaf pieces.Utilize this opportunity to check the innards of your block Those buggers just love to end up where they damage the engine.<br />While you are at it replace the other one as well.<br />Tell me is the Tivoli still as great as it was 30 years ago?? Is cod fishing in the fjords still as good as in those days??<br /><br />One nostalgic tosk fisherman

Re: Help Evinrude 35Hp Still one cylinder

Manny thanks for your reply, rolmops.<br /><br />Il´ have to do it then. Il´ get a gasket set and disassemble. I suppose no harm has been done yet, as compression is still fine, so i must have been luckey some how, anyway.<br /><br />Tivoli is exactly the same as ever. We go there every year with the kids - we have four of which the one is grown up now. This place has a spirit of its own.<br /><br />Cod fishing is still great. There has been years where there were quite few of them, as the Polands fish a low at deep water, and they dont care of rates - but it is getting better now again. But thats a winter feature. Now spring is on its way - and il´rush to get boat ready. Here in Praestoe we have hornfish in April - its kind of mini swordfish - delicious and funny to chatch. We had the most rainy february ever mesured - and now the warmest april is probably on its way. We had sunny weather for 14 days now and temp beyond 15 deg celcious every day. A bad motor hurts then. When were you here ?

Re: Help Evinrude 35Hp Still one cylinder

Hello again.<br />In '72 I spent six months on a catamaran sailing back and forth between Copenhagen, the Shetland islands,the Moldefjord and the Lofoten.