Mantis tiller puzzle

[38racing]

I have a model 7224 with sv5c/2 engine. I pulled it from shed tonight. It was running when put there last fall. Tank was empty. I added fresh mix. When I primed it the bulb collapsed and stay so. As test I spray carb cleaner. It would fire but never stay running. I discovered that it was getting no fuel from tank. Filter was plugged and on removing from tank fuel line just broke in pieces. So after repair it primed a nice stream through return line into tank. But now I can't get any fire at all, not even on the carb cleaner spray. New plug when removed and grounded has good blue spark. Compresson six pulls is 110. Other test I did was ohm from plug lead tip of coil wire to ground. Reading fluctuates when I move wire including infinity. I'm going to repeat test tomorrow ensuring I maintain contact with the lead when moving the wire. I'm wondering if maybe the muffler somehow plugged during my carb work although seems a stretch but I'll pull it tomorrow too. Replacement coils seem pricey but aliexpress appears to have one for my engine model for $29 cdn. Any thoughts on the no fire?

[KE4AVB]

It been a while since I seen a SV5 engine but if I remember the coil's high tension lead use a wire coil for the plug contact that is just pushed into the lead. These tends to break the lead internal wire so you may just need to trim the lead a little and re install the contact.

Many old string trimmers use this system of contact attachment for the 5mm leads.

[38racing]

I'm wondering if it's possible that i flooded cylinder by lifting it to working height with a hoist having cylinder low for awhile? Not sure how that could happen on a 2 cycle. Going to remove plug and let sit a while.

[KE4AVB]

It is possible with cube carbs where the metering diaphragm has stiffen and also if the metering needle rings the rubber tip. Pressure testing the fuel inlet side of the carb should tell if it is either case. I even had one that would pass the test and still leak during operation of the engine.

[bgsengine]

What KE4 said - Sounds like you maybe flooded engine a bit. Make sure you are using the CORRECT spark plug (They can be finicky about that, like some Echo's) also try a different plug (possible a piece of carbon broke free and lodged in plug between insulator and causing a short) Also, you say 6 pulls - you don't count pulls when testing compression - You just crank 'er over until the compression gauge needle stops moving... could happen in 3 pulls, could happen in 10 .. 110 is kind of the low end of compression readings for those. If it won't fire on a shot of carb cleaner, you very well may have flooded it - hang it with plug hole facing down overnight plug removed, (and pop off carb & fuel tank) Raw fuel can get into the crankcase and then it gets sucked in as liquid fuel (which won't burn) and thus you won't get it to fire. Before putting plug back in next day (and assembling carb & tank) make sure you crank it over a bunch of times to be sure you evacuated all of it. They're HARD to get started again after they get flooded (or overchoked) even with a shot of carb cleaner.

Finally - Those engines you should get yourself a grommet & line kit , new fuel filter, and replace all lines & filter every year as part of maintenance. They're relatively cheap - even if you buy the OEM Echo 90069 kit (or buy a box of 90014 fuel line, a 5-pack of grommets, and a few extra fuel filters and make your own kits.. may also want to check or test the pressure relief check valve it should hold no more than 3 - 7 PSI pressure and allow ZERO vacuum (if it holds NO pressure, may want to replace it too)

[38racing]

What KE4 said - Sounds like you maybe flooded engine a bit. Make sure you are using the CORRECT spark plug (They can be finicky about that, like some Echo's) also try a different plug (possible a piece of carbon broke free and lodged in plug between insulator and causing a short) Also, you say 6 pulls - you don't count pulls when testing compression - You just crank 'er over until the compression gauge needle stops moving... could happen in 3 pulls, could happen in 10 .. 110 is kind of the low end of compression readings for those. If it won't fire on a shot of carb cleaner, you very well may have flooded it - hang it with plug hole facing down overnight plug removed, (and pop off carb & fuel tank) Raw fuel can get into the crankcase and then it gets sucked in as liquid fuel (which won't burn) and thus you won't get it to fire. Before putting plug back in next day (and assembling carb & tank) make sure you crank it over a bunch of times to be sure you evacuated all of it. They're HARD to get started again after they get flooded (or overchoked) even with a shot of carb cleaner.

Finally - Those engines you should get yourself a grommet & line kit , new fuel filter, and replace all lines & filter every year as part of maintenance. They're relatively cheap - even if you buy the OEM Echo 90069 kit (or buy a box of 90014 fuel line, a 5-pack of grommets, and a few extra fuel filters and make your own kits.. may also want to check or test the pressure relief check valve it should hold no more than 3 - 7 PSI pressure and allow ZERO vacuum (if it holds NO pressure, may want to replace it too)

On the plug issue. Mantis says cj6y or ngk bpmr7y. In it before was a bpmr7a. My suppliers shows cj6y crossing to bpmr7a. What's the difference on ngk ending in a or y. I put in new plug that crossed to cj6y.
I redid my coil wire test with better contact. 2500 ohms. Moving wire didn't cause changes this time.

[bgsengine]

What KE4 said - Sounds like you maybe flooded engine a bit. Make sure you are using the CORRECT spark plug (They can be finicky about that, like some Echo's) also try a different plug (possible a piece of carbon broke free and lodged in plug between insulator and causing a short) Also, you say 6 pulls - you don't count pulls when testing compression - You just crank 'er over until the compression gauge needle stops moving... could happen in 3 pulls, could happen in 10 .. 110 is kind of the low end of compression readings for those. If it won't fire on a shot of carb cleaner, you very well may have flooded it - hang it with plug hole facing down overnight plug removed, (and pop off carb & fuel tank) Raw fuel can get into the crankcase and then it gets sucked in as liquid fuel (which won't burn) and thus you won't get it to fire. Before putting plug back in next day (and assembling carb & tank) make sure you crank it over a bunch of times to be sure you evacuated all of it. They're HARD to get started again after they get flooded (or overchoked) even with a shot of carb cleaner.

Finally - Those engines you should get yourself a grommet & line kit , new fuel filter, and replace all lines & filter every year as part of maintenance. They're relatively cheap - even if you buy the OEM Echo 90069 kit (or buy a box of 90014 fuel line, a 5-pack of grommets, and a few extra fuel filters and make your own kits.. may also want to check or test the pressure relief check valve it should hold no more than 3 - 7 PSI pressure and allow ZERO vacuum (if it holds NO pressure, may want to replace it too)

On the plug issue. Mantis says cj6y or ngk bpmr7y. In it before was a bpmr7a. My suppliers shows cj6y crossing to bpmr7a. What's the difference on ngk ending in a or y. I put in new plug that crossed to cj6y.
I redid my coil wire test with better contact. 2500 ohms. Moving wire didn't cause changes this time.

BPMR7A VS BPMR7Y

Thread Diameter 14mm Thread Diameter 14mm
Thread Pitch 1.25mm Thread Pitch 1.25mm
Seat Type Gasket Seat Type Gasket
Reach 9.5mm (3/8") Reach 9.5mm (3/8")
Hex Size 3/4" (19mm) Hex Size 3/4" (19mm)
Terminal Type Removable Nut Terminal Type Solid
Overall Height Bantam Overall Height Bantam
Gap .028" (0.7mm) Gap .028" (0.7mm)
Center Electrode Material Nickel Center Electrode Material Nickel
Type Standard Type V-Cut
Size 2.5mm Size 2.5mm
Projection Projected Projection Projected
-------------BOTH IDENTICAL HERE-------------
Ground Electrode Material Nickel
Type Standard
Quantity 1
Specifications Resistor Yes
Resistor Value 10k Ohm
Heat Range 7
Torque Specs Cast Iron: 18-25.3 lb. ft. Aluminum: 18-21.6 lb. ft.


Only difference between the A and the Y is the V-Groove electrode which promotes a more formed spark. (Either plug at one time had both removable nut or solid center terminal, but they've been phasing out the removable nut terminals as the NEED for them has pretty much died out (Plug boots made to fit just the threaded part so the nut would have to be removed, or plug wires that actually fastened to plug by the nut really are not made any more..)

[38racing]

Thanks. Interesting a versus y for he groove. In bk5r they end with e for groove and es for non groove.

[KE4AVB]

I think you the plug numbers wrong. It should BKR5E and BKR5ES.

IF you look at the NGK decode chart the "E" just indicates that plug has a 19mm thread reach or has a special design firing tip. The "S" indicates it has an Copper core center electrode.

But no one bothers to look in the downloads. I got two NGK catalogs and the decode chart posted under the Briggs downloads under Spark Plugs.

[38racing]

I think you the plug numbers wrong. It should BKR5E and BKR5ES.

IF you look at the NGK decode chart the "E" just indicates that plug has a 19mm thread reach or has a special design firing tip. The "S" indicates it has an Copper core center electrode.

But no one bothers to look in the downloads. I got two NGK catalogs and the decode chart posted under the Briggs downloads under Spark Plugs.

right, I always get those numbers out of order. I forgot the downloads section. Tried google as I knew I had seen the numbering breakdown before but google didn't throw it out.