7.5 HP Gamefisher dies, won't start

[mrcrabs]

Re: 7.5 HP Gamefisher dies, won't start

Think I'm on the right track?

could be, read tommy 2 strokes post about timing his rebuilt engine.

 

[MahtyMaht]

Re: 7.5 HP Gamefisher dies, won't start

Just got back from the creek with that thing - it did really well with the transition from high to low RPM. I killed it a couple of times, and it lit right back up, so I thought maybe I had it. I ran it around for 30 minutes, and it still acted like it might die coming down from high R's, but it was very manageable. I took it back to the ramp and killed it, and it would not start. I'm heading over to take a looksee @ tommy2strke's timing adventure, because I got no idea about it.

 

[mrcrabs]

Re: 7.5 HP Gamefisher dies, won't start

the butterfly rod and timing cam should have a smooth but close relationship through out the timing/throttle's advance to wot

 

[Tom @ Buzzard Bluff]

Re: 7.5 HP Gamefisher dies, won't start

<I get it home, and I notice the timing cam doesn't contact the throttle linkage till the carb is at half throttle. Huh? Wut wut? I've reset the cam so it starts advancing the timing just above idle, and maxes out at max throttle. We'll see. Think I'm on the right track?>

Maybe not. I took a look at the 'link & sync' instructions in my Intertec manual (did you ever get a shop manual????) and the instructions are so extensive and confusing I didn't even try to relay them to you since I got confused myself!

On many outboards the throttle arm isn't supposed to begin to move until the timing/throttle control is almost on top of the start mark. So you may have added to your woes. On most motors (Don't recall in the case of Eska) there is a mark on the throttle advance cam on the mag plate to indicate where in the advance cycle the throttle arm must first contact the cam and start to move. Check for a mark or line on that cam.

 

[Tommy Two Stroke]

Re: 7.5 HP Gamefisher dies, won't start

The recent timing situation I encountered was a case where Tecumseh's timing procedure made the engine start/run/die much worse than it had been doing with the original timing setting. In short, I found that on my 7.5, the pin on the carby needed to contact the ignition advance cam very early in the ignition advance cam's travel for the engine to start and run properly. Just beyond the "start" position on the tiller handle is where I ultimately set it to initially contact on mine. There is probably some variation in the setting from engine to engine, but it seemed that getting enough fuel early into the advance cam's travel with this setting.

Another thought - any chance you might have a hole in your float so that it's filling up with gas and not floating properly? I replaced my corroded brass float with a new Tecumseh plastic float, with no damping spring, and set the float height using a 11/64" drill bit as spec't by Tecumseh - works well w/ no carb leakage.

A final problem it could be, if you've exhausted everything else including ignition, is a bad crank seal. I've seen a case on a friend's Eska where the crank seal would leak only a bit when cold (verified with penetrating oil when we took the engine off the leg), allowing the engine to start and run, but increased rubber softening (most of them are nitrile rubber) at higher temp's made it leak sufficiently so the engine was difficult to start when hot. There could be some weird interaction between your lower seal and the crankshaft if the crank is corroded in this area - often seems to be the case on Eskas that have been run in salt water at some point in their past lives.

 

[MahtyMaht]

Re: 7.5 HP Gamefisher dies, won't start

Hey, Tom @Buzzard - I never noticed a mark on that sucker, but you can belive, I'll be sliding over it with a magnifyin glass soon. Tommy2, I parked that float in a cup of fuel all morning earlier in this process, no loss of ride height. Oh, my Jesus God, it just can't be the lower crank seal. I did see where a guy found out Chicago Seal had a dead-bang match for it, though. And no I never got a service manual for it - Just that generic Tecumseh thing covering various two strokes. Is there a good test for that crank seal?

 

[Tom @ Buzzard Bluff]

Re: 7.5 HP Gamefisher dies, won't start

<Is there a good test for that crank seal?>

A crankcase leak-down test is normal procedure on 2 strokes but the kit to do it is outside my financial reach. A shade-tree method is a dish-soap solution in a spray bottle. Put the engine on bottom dead center and quickly spray the seals to see if you have excessive leakage. A tiny bit is normal but if it looks like an aquarium pump it's " Oh *****" time.

 

[MahtyMaht]

Re: 7.5 HP Gamefisher dies, won't start

So if a guy was looking to do a somewhat more upscale shade tree crankcase pressure test, and he had a pressure gauge, regulator, compressor, and some pipe fittings laying around, what kind of pressure and hang time would he be hoping for? I looked at the timing cam, no marks, so I have it set to start moving the throttle at the top of the 'start' mark. Starts and runs fine, but if I kill it after 30 minutes of hard running, it insists on being cooled completely down before it'll light off and run again. I can't replicate the problem in the trash can, 'cause I can't load it enough. Keep meaniing to take a plug wrench, so I can see if it's sparkin' but I keep forgetting it. I don't know how you'd set the timing with an electronic ignition module either.

 

[MahtyMaht]

Re: 7.5 HP Gamefisher dies, won't start

Finally remembered to take a plug socket with me. Ran around 20 min or so thoroughly warmin' that sucker up, killed it, wouldn't start, so I snatched the plug, and it was a lovely brown, but it was bone dry. I took the quick disconnect off the engine end of the fuel line, primed 3 drops of fuel into the plug hole, reinstalled, it lit right up. This happened several times on that trip. most of those times, there was a fuel/air mix in the throat of the carb that looked like mashed potatoes. Still the plug stayed dry. What in the he77 kind of fuel delivery problem have I backed into here?

 

[mrcrabs]

Re: 7.5 HP Gamefisher dies, won't start

sound as if ye be suckin air someplace mate, the crankcase pulse hole tends to erode the carby gasket on some of the thicker gasket material. Also have a look at your air vent on yer gas tank and check them fuel lines and the gas shut off valve.

 

[MahtyMaht]

Re: 7.5 HP Gamefisher dies, won't start

You could be onto something here, Mr. C. It occurs to me, too, that it was doing a little hunting, or surging out there. I wasn't sure at the time if it was wandering rpm, or squirrelly river currents. It does have kind of a thickish carb gasket, and I've never changed it. I'll investigate, and report.

 

[MahtyMaht]

Re: 7.5 HP Gamefisher dies, won't start

OK, Mr Crabs, I screwed the pooch with regard to the diagnostic utility of the changes I made, because I made three at once. I changed the carb/reed plate gasket, covered a gap in the starter shroud, and set the timing cam to engage the throttle a tad later. Motor makes a lovely transition from high to low R's, but it still surges at WOT, and after a full hour, it was a nuisance to restart, but less than it has been. The gap in the starter shroud is because I scarfed the shroud off a later Tec 2stroke snow blower that had a 110V electric starter mounted. I used that nasty lookin' aluminized tape to cover that starter gap, because I was afraid it was scraggin' the flywheel's ability to run air over the engine, makin; it run hot. Here's something of possible interest: I happened to see the underside of the cylinder today, and I noticed oil staining around the rectangular gasket seam where the exhaust gets watered. The bolts have those stupid ***** 12 point bolts. I notice the exhaust sound seems to wander and change at WOT. Am I losing it at this gasket? Would that play screw around with WOT RPM?

 

[mrcrabs]

Re: 7.5 HP Gamefisher dies, won't start

I happened to see the underside of the cylinder today, and I noticed oil staining around the rectangular gasket seam where the exhaust gets watered. The bolts have those stupid ***** 12 point bolts. I notice the exhaust sound seems to wander and change at WOT. Am I losing it at this gasket? Would that play screw around with WOT RPM?

If your losing back pressure its highly possible to surge and srew with WOT, the oil is obviously coming through the exhaust, your surging could still be the timing off or some part of the electronics is failing with heat added such as the SSI or Pulse Transformer. You may want to go to Ed Stoller's web site and read through and see what test you could perform on the PT.

 

[MahtyMaht]

Re: 7.5 HP Gamefisher dies, won't start

This motor originally used points. I used one of those Atom Computer Ignition modules from Banta Saw to get away from points. http://www.bantasaw.com/catalog/browse.asp?i=199
It seems to work really well. When the motor was fully up to temperature and would not start, it was still sparking. The motor seems to be running cooler, too with the gap in the blower housing closed.

 

[mrcrabs]

Re: 7.5 HP Gamefisher dies, won't start

I usally don't do this but I slept on your problem last night and it might have something to do with me having the flu but I considered every thing I thought could cause surging and hard starting after getting warm and since we have worked through everything it isn't so far, I have one last suggestion.
If you pull the flywheel look for scratches on the magnets and worn spots on the charge coil, these are dead give away for weak bearings..and when you have weak bearings you have bad crank case seals, thus losing crank case pressure between strokes.

 

[Tom @ Buzzard Bluff]

Re: 7.5 HP Gamefisher dies, won't start

<This motor originally used points. I used one of those Atom Computer Ignition modules from Banta Saw to get away from points. It seems to work really well. When the motor was fully up to temperature and would not start, it was still sparking. >

A properly adjusted points/condenser magneto system works wonderfully well. I find I very seldom have to replace the points on veterans that I like bringing back to life. Unless they are badly burned (indicating a bad condenser) or the block that follows the cam worn off I simply disassemble, clean in thinner and polish them to a high sheen on a piece of worn-out wet or dry sandpaper, reassemble, adjust and degrease by dragging a few strips of paper cut from a heavy brown paper bag.

Since the points replacement modules have been indicted in some instances for changing the timing I would retrofit a good set of points to get back to 'square one' and see if the surging goes away.

<The motor seems to be running cooler, too with the gap in the blower housing closed.>

To function properly the motor MUST have the original shroud!

I looked for the article on checking crankcase compression---thought I'd bookmarked it but no luck. Try googling 'checking crankcase compression on two cycle engine'. I suspect that lower crankshaft seal.

Afterthought edit: closely inspect the area under the flywheel to see if you can find oily deposits caused by a leaking upper seal before doing anything else! Whether you do or not carefully degrease the mag plate so you are starting from scratch in order to recognize the problem down the road.

 

[MahtyMaht]

Re: 7.5 HP Gamefisher dies, won't start

Mr. Crabs, I'm flattered by the extraordinary attention. I have polished the flywheel magnets till they shine, because I know what rusty ones can do to ya. I also set the coil core gap absolutely as close as I could get it without interference from the fly wheel. During this process, I did see some 'shake' in the upper end of the crank. I declined to put the dial indicator to it, because I didn't want to know the details. Gonna have to rethink that whole approach, it appears. How much radial play can I safely have? Tom, I think I'll stay with this module, and hope I can get the timing optimized by trial and error. I have had the mag plate off, and I put some grease in there, then set the tension on that set screw lookin' thingamajuter. I'll thoroughly clean up the top of it around the crank and keep an eye on it. I'm gonna find some info on pressure testing. We'll get there, gentlemen, we'll get there. I really appreciate the help here, you guys are the shizzizzle!

 

[MahtyMaht]

Re: 7.5 HP Gamefisher dies, won't start

Stepkid's 454 was leakin' thruthe weephole, so I dealt wi that, but The gauges are yankin' my chain, too, so that's next. I hterefore, amy not be able to advance the eska plot this weekend. What I'm seeing on the net about pressure testing 2 strokes suggests that I'm gonna have to make some block-off plates to make it happen. Not today.

 

[mrcrabs]

Re: 7.5 HP Gamefisher dies, won't start

order you a lower crank seal and retainer ring, your lock ring should come out ok, the lower seal is really easy to change once you get past the lock ring...not much to it really unless the bearing is bad. the upper should be about the same although the lock rings can be tuff...you just need to knock'um around a bit to free them up.

 

[MahtyMaht]

Re: 7.5 HP Gamefisher dies, won't start

I usually don't do this but I slept on your problem last night and it might have something to do with me having the flu but I considered every thing I thought could cause surging and hard starting after getting warm and since we have worked through everything it isn't so far, I have one last suggestion.
If you pull the flywheel look for scratches on the magnets and worn spots on the charge coil, these are dead give away for weak bearings..and when you have weak bearings you have bad crank case seals, thus losing crank case pressure between strokes.
__________________
BOIOIOIOINNNNGGGG!!!! TELL Him wgat he's won, Johnny!
I think it's what I have consistently tried to headinthesand my way around all along -seals/vacuum leak. I put a dial indicator to the flywheel, yanked back and fourth, got .030" total radial play. Now there's just no way that's ever gonna be OK. Aint no crank seal in the world gonna cover that kind of slop. I'm gonna have to do a Tommy2stroke on this sucker, aren't I? Lock rings? Uh, er, Mr. Crabs - is there something I should know? Let's start with, 'what's a lock ring?'
ourfatherwhoartinheaven............ I'm goin' in. What about bearing replacement while I'm in there?