150 evinrude gas hog

[jere baker]

1980 e150trxcs motor.idles like a champ accelerates slow, top rpm 4000, prop 15 x 17,speed 35, gas hog big time, large amounts of spit back, under hood covered with oil.<br />Work done so far; carbs removed and cleaned ( were very clean ) checked inlet needle and seats OK,compression check 3 cyl at 100lbs,2 at 95lbs and 1 at 90lbs, pulled reeds, reeds lay on cage with no light visable. none broken or chipped. Pulled exhaust plate, small amount of carbon ,none around ports.<br /> Am I headed to the store for pistons or have I got other problems. Not use to boat motors but do know 2 cyles and 10lbs of differants won't make a snowmobile motor run this bad. I have rebuild a 150 for a friend of mine but have know experance at trouble shooting boat motors.<br /> I need someone to stop me before I start buying things because I can't stand to have a motor not run right, and of course this has to be mine.<br /><br /> Thanks.

 

[JB]

Re: 150 evinrude gas hog

Howdy SledMech.<br /><br />Did your engine ever run well for you? 4000rpm at WOT is too little. It should turn 5500.<br /><br />If it has run well in the past you may be down a cylinder or two. You can check that at idle by killing the cylinders one at a time. If no difference, dead cylinder. Two dead ones side by side are a carb problem. Three in a row is a powerpack problem.<br /><br />If 4000rpm has always been top end you may be overpropped. That could also account for the small variation in compression. A good decarb job should help that part.<br /><br />Let us know about the history and the cylinder check.

 

[steelespike]

Re: 150 evinrude gas hog

Sled, First get a manual(a must).<br />Check my other posts for where.<br /> Not an expert but how about a bad upper,crank seal I think this would cause the mess under the hood.Also poor performance from fouled intake air<br /> and poor crankcase pressure and vacume.<br />If you have any true spitback through the carbs<br />the only thing that i know to cause it would be bad reeds.let us know what you find mabe sombody can come up with something.<br /> Good luck.

 

[jere baker]

Re: 150 evinrude gas hog

thanks for the quick reply JB<br />I just got the boat last month so of course the previous owner told me how great it ran I really don't know its run like this ever since I put in the water.<br />The motor runs smooth as silk at idle in fact you can't detect a skip anywhere in the whole power range. The motor runs just like its got inlet needles that are leaking but they look alright. I was told that the prop is really a rpm prop and I should be pulling rpm's with no problem.<br />One thing I just descovered is the intake has been changed., as I was cleaning the gasket material off I descovered someone has hack sawed some mounting flange off the bottom and I'm sure it wasn't the factory.This opens up a whole bunch of questions like maybe these carbs didn't come on this engine. Do you thing the compression rates I gave are bad enough to create this typ of problem on a boat motor? Also do you know where I might get the jet spec's on this carbs.<br />I have the exhaust plate off and there was some carbon but nothing to amount to much in the ports themselves.<br />I really wasn't to happy with the type of inlet needles that were in the carbs they seemed alittle loose to me so I'll replace them just to ease the mind.<br />My biggest problem is that I don't know that much about boat motors but if this was a snowmobile motor I'd have a much better shot at it. The moto runs just like a snowmobile motor with way to big of jets in the carb and then as soon as yu drop back to the mid or idle circuit everything is OK.<br />thanks sledmech

 

[jere baker]

Re: 150 evinrude gas hog

Thanks for the info spike.<br />I have a manual which tells me everything about how to take it apart and put it back together it just doesn't tell me why I should take it apart.<br />My past experance with two strokes has been that a crank seal will make a motor run lean plus usally a cyl. or two will drop dead at idle which isn't the case with this motor. Big question is with the compression specs I gave should I be looking at a rebuild. Don't know enough about boat motors to know how touch'y they are about compression.<br /> Later sledmech

 

[JB]

Re: 150 evinrude gas hog

Howdy Sledmech.<br /><br />The biggest liar in the world is a V6 outboard that is idling on three or four cylinders. The only reliable way to know is to disable each cylinder and watch for rpm drop. No drop, no power.<br /><br />The engine acting like a sled engine running too rich is an engine that is lugging and not reaching its power range.<br /><br />You may have some engine power issues but if all 6 are making power you should be reaching 5500-6000rpm. I think you need to borrow a prop with a couple of inches less pitch and try it out.<br /><br />As Steelspike says, a bad upper seal could well cause a lot of your symptoms and is worth checking out. I don't think, however, that it would drop you 1500rpm on a V6 'Rude. It only affects the top crankcase.<br /><br />Good luck and keep us posted.

 

[ROGER67]

Re: 150 evinrude gas hog

I'm going to try to tell you something on your prop there guy you need to go for a 14 1/4 x 23 and you will get the wot your looking for I tried the 15 x 17 and got the same ordeal it will be better on gas you are over working the motor with the wrong prop guy ,,,,,have a good day

 

[Dhadley]

Re: 150 evinrude gas hog

Roger67 - Are you saying to go to a bigger prop to increase RPM's?<br /><br />?????

 

[jere baker]

Re: 150 evinrude gas hog

Thanks for all the replies,<br />I probably could of saved myself some work if I had talked to you guys earlier. I'll put the thing back together with some new inlet needles and see if I can tell if I'm loosing cyl. I know on a sled with 3 cyl. if you drop one it becomes a real slug beacuse now its a compressor instead of a power producer.I just felt that it ran to good to have one or two cyl dropping but we'll find out., as long as know one seems to concerned about my compression check I'll but that in the back of the book.<br />Thanks again we'll be back when I've got it fired up.<br /> Sledmech

 

[jere baker]

Re: 150 evinrude gas hog

Took me awhile to get back . I've put the motor back together and checked the plug firing by pulling wires one at a time. All the cyl. make a change when pulled, of course the 90lb and two 95lb cyl. didn't have the same effect as the 100lb cyl's did. I put the boat in the water today and found that all I've done is take the motor apart and put it back together, good practice I guess.<br />Max. RPM's 4100, real slow pulling up onto plane,<br />just flat down on power. Motor runs real rich, of course it would with no power.<br />I'm hopping somebody will tell me not to get upset with the compression or else tell me to start tearing it down.<br />I haven't checked for the 7/16 fire gap or the timing. I'll do that next and hope in the mean time sombody out there will steer me along.<br />Everybody keeps telling me how well this should run but I'm not seeing it sio far.<br /> Later sledmech

 

[Yepblaze]

Re: 150 evinrude gas hog

Get a prop and achiev the proper RPM and I'll bet it turns into a whole new animal. (running good) Lugging it around like you are is only taxing it.

 

[rolmops]

Re: 150 evinrude gas hog

Crazy question.<br />When you run at full power does she come up to plane or is her nose sort of pushing into the water?<br />Reason why i ask is that if your outboard sits at the wrong angle it will push her nose into the water and work a lot harder but get a lot less done.

 

[wilde1j]

Re: 150 evinrude gas hog

What boat are you running and approx all up wt? Compression numbers are a little on the low side, but shouldn't cause down on power deal.<br /><br />You may want to run decarb thru engine (may have stuck rings).<br /><br />You seem to be on the right track in checking ignition stuff, like spark length, etc. I would check the spark plug wires and coils for cracking, bad terminations, etc. as well as checking the stator, timer base.<br /><br />Good luck!