Massimo 500 will not start

[JohnnyB]

My Massimo 500 will not start. I’ve checked all the obvious things. It turns over just fine. fuel, spark, fuse box are all good. I can’t figure it out. Any ideas would be greatly appreciated. Thank you.

[T-boss 410]

Is it fuel injected? If so, maybe the injector is bad?

[IslandHopper]

If the engine is only cranking but not popping, backfiring etc. Then like T-Boss 410 said, the injector could be bad. Massimo does not have a inline  fuel filter, just a screen. This apparently leads to a lot of bad injectors. A common bad injector symptom is the motor will start and idle but fall off under acceleration.  In your case, there is nothing, so let’s look further.

Check the spark with a GOOD TESTER. I’ve been an equipment mechanic for 30+ years and I can’t tell you how many times I’ve seen a spark plug fire when laid on the engine block THEN NOT FIRE when it’s installed and under cylinder pressure.

Is the fuel fresh? In my shop it’s VERY common for flat fuel to cause a no start

If you truly have good spark and fresh fuel then  try this quick trick. 
Take the air filter off and shoot a little carb cleaner or starting fluid into the intake. Then crank the engine over....

1) Still nothing. You have a valve issue or a compression issue. (It’s not burning the fuel)

2) Motor starts  then dies. The Fuel Injector is most likely plugged or bad. (You’re not getting fuel into the cylinder)

I hope this helps.
 

[JohnnyB]

Thanks fellas. It only has about 100 miles on it. I’ll try the starting fluid. Might pull the plug an shoot some in the cylinder.

[T-boss 410]

Hey, for future peace of mind, I would put a fuel filter in the line somewhere between the pump and the engine. Surprisingly, mine does have a filter mounted to the frame just past the pump. Don't know if Massimo decided to add one due to some warranty repairs, or what the cause was. I'm sure you could find a filter that's designed to work with a fuel injection system and can be added to the rubber line. 

You may be able to remove the injector and clean it, assuming that it ends up being your issue. 

[JohnnyB]

I’ve taken off the injector and turned on the key. It shoots out of it like nobody’s business. However, I pulled the plug and it doesn’t seem to be getting fuel into the cylinder. Stuck valve maybe?

[T-boss 410]

Is the injector pre or post butterfly valve? Assuming that it's similar to an automotive throttle body fuel injection system, that puts the injector before the butterfly valve. In that case, it could be the butterfly valve. But if it's similar to mine, it's a mechanical butterfly valve, and should be opening and closing via a cable. You can check that. 

You mentioned that the coil is getting power. Have you confirmed that the spark plug is actually firing? Maybe it's a overhead valve out of adjustment?

Just spitballing here, trying to help. 

[JohnnyB]

Post, it’s after the throttle body. I’m not sure. I was wondering if maybe there is ice inside a valve somewhere? Doesn’t seem to be getting fuel. It’s between the injector and the cylinder I guess? I’m going to get some starte fluid and spray it directly into the spark plug hole.

[T-boss 410]

But you have a functioning fuel pump, correct? I don't know what would be obstructing the fuel from reaching the cylinder. 

[JohnnyB]

Right. The fuel pump is working, the fuel injector is working, when I pulled out the spark plug, it fired a heavy blue arc. I’m going to try and get some heat to the engine. I’m hoping that it’s only ice causing blockage to the cylinder. Other than that I have no idea.

[Travis]

Wonder if air got or is getting in the injector system, can you crack the lines loose just before the injector and crank it over to bleed?

[JohnnyB]

It’s getting fuel to the cylinder now. Still won’t fire. Won’t even hit a lick. I fired the system to burn out the cylinder but nothing after. I wonder if there’s water in the fuel? Spark plug still arcs when it turn it over.

[Randy Stevens]

It could be moisture in fuel, not uncommon. For future reference , I burn nothing but highest octane in mine and use good quality fuel such as BP. Hisun 550 and runs like a champ. Good luck buddy!

[Ben1098]

Sounds like slop for fuel.  pull the fuel pump connector at fuel tank top.......this keeps the slop from loading up the cylinder.  Pull spark plug and use a propane or MAPP torch to dry out the insulator tip.  Reconnect to the spark plug cable and lay it on the frame away from engine.  Have remote starter or helper crank over engine while you give it the finger over spark plug hole compression test....should blow off finger with a POP.  Engine oil is cold....cylinder/rings might be dry....wet them by fogging the cylinder with WD40.....more compression????  If not, run the valves and be careful NOT to stop in the cams compression release area....i.e. go past TDC a bit (25 deg) then roll back to TDC.

Reload the spark plug.....remove air filter lid....start cranking and then give it a shot of the go juice (starter fluid)..should light off and then die....repeat several times to warm the engine some.  Reconnect the fuel pump connector......give a short shot of go juice and crank over.  Slop will run poorly or not at all.  If you have slop, drain the fuel tank with a hand squeeze pump.  The fuel pump "holds" some fuel in the cup.  You have to bleed/rid the system of the slop.  Remove hose from injector (warm hose to make soft and pliable so no damage and crumbs break loose.  USE gasoline (no OH/water mix) and fill tank.  KEY ON-OFF cycle to pump/fill the line with fresh gasoline....run into a clear jar and see if there is some phase separation------gas on top and yellow soup on the bottom.  The injector will have slop yet so use the starter fluid to enable the engine to run and push thru the slop....IF all good, the motor will now run only on the FI system.

The cold temp input to ECU will squirt more fuel (mimic a choke on carb) so a batch of slop can wet down the spark plug and cause it to blow out under compression.

[cliffyk]

On 2/4/2021 at 8:26 AM, IslandHopper said:

If the engine is only cranking but not popping, backfiring etc. Then like T-Boss 410 said, the injector could be bad. Massimo does not have a inline  fuel filter, just a screen. This apparently leads to a lot of bad injectors. A common bad injector symptom is the motor will start and idle but fall off under acceleration.  In your case, there is nothing, so let’s look further.

Check the spark with a GOOD TESTER. I’ve been an equipment mechanic for 30+ years and I can’t tell you how many times I’ve seen a spark plug fire when laid on the engine block THEN NOT FIRE when it’s installed and under cylinder pressure.

Is the fuel fresh? In my shop it’s VERY common for flat fuel to cause a no start

If you truly have good spark and fresh fuel then  try this quick trick. 
Take the air filter off and shoot a little carb cleaner or starting fluid into the intake. Then crank the engine over....

1) Still nothing. You have a valve issue or a compression issue. (It’s not burning the fuel)

2) Motor starts  then dies. The Fuel Injector is most likely plugged or bad. (You’re not getting fuel into the cylinder)

I hope this helps.
 

^^^Good information^^^

A variable gap spark tester like this one cam detect he issue IslandHopper describes re; The plug firing under atmospheric pressure but not under compression.

Set the tester  toa  8 to 10 mm gap--most modern ignition systems will fire across a 10 mm gap in free-air, if not the coil is likely weak...

[IslandHopper]

Ben1098 put some good info here. I have had situations where a customers’ fuel is so bad that even if I put good fuel directly into the cylinder, the bad fuel spraying in from the injector IMMEDIATELY diluted my good fuel and it wouldn’t burn. I had to completely remove the bad fuel source before it would even pop.

[cliffyk]

This damned ethanol contaminated gasoline they make us buy has a shelf life of about 3 months, unless in a very tightly sealed container¹--and that's here in FL were we have just 10% booze in the gas. On anything with  carburettor that has been siting for more than 4 months the first hing to do is rebuild (or at least disassemble and clean) the carburettor. Lat Fall I repaired a number of "no-start" generators for my neighbours that had been improperly stored; they all had nasty jellied masses of pinkish crap in the float bowls. I've not found that any of the commonalty available "fuel stabilizers" prevents his--it's that blasted alcohol in the gas--maybe an olive or some vermouth would work--IDK?.

---------------------------------------------------------------------------------------------------

¹ - Take the spout off your gas cans and put on a good tight cap.
² - They just shut them off after last the hurricane season and let them sit for 9 months--they did not drain the fuel tank and run 'em dry--then put a cup or two of stabilizer in the tank and crank 'em over a couple times. 

[Travis]

Pink stuff in the bowl? That sounds like out of Date StaBil.  I've cleaned more carbs for people who've used Stabil than any other treatment. I started using StarTron. Haven't had 1problem with my own equip.

[cliffyk]

ON my carburettor stuff that sits i generally drain the tank then run 'em 'til they stop. Next give a squirt or two of Marvel Oil from a pump can  into the fuel line and crank it over as bit--fresh fuel when 'tis the season and they just pop right off...

[IslandHopper]

100% right on the pink junk being Stabil. It’s no help for Ethanol. This is a discussion  I have with customers all the time when I test their “100%” gasoline and show them 4-8% ethanol in it. I always recommend the best non-ethanol you can find PLUS an ethanol treatment. Ethanol-shield*  and Startron*  have both worked ok. 

[cliffyk]

I'm pretty sure my neighbours don't even know what Stabil is--what I got out was "pinkish", but mostly clear jelly--a nearly perfectly "float bowl" shaped ring (minus the float) of he stuff...

[slowpokewy]

I have a Massimo 500 2016 side by side I'm not getting fuel from the fuel pump to the carbonator.  We have changed the fuel pump and still no fuel.  It will start and run for a short time on starting fuel or gas..  What would keep the fuel pump from pumping fuel?  Can you install a fuel pump incorrectly?  HELP

[Ben1098]

Do you have a mini-fuel tank (1 Pint) hanging behind the pass seat?

Do you have the vac pulse fuel pump...little box with fuel IN/fuel OUT/vac hose to carb area.

Yes, can be hooked up wrong.  Seen a previous post of the whole setup picture diagram that was good.  DOCTOR parts stove was source (forgot exact handle).

Pump has IN and OUT with vac signal usually a smaller port.  INPUT is suction so no leaks to a good in-tank fuel filter---meaning can gas be sucked into the pump input?  Vac signal---no leaks in hose and connected to manifold.

OUTPUT goes to the little tank and partly fills the tank to the OVERFLOW RETURN level connects back to the fuel tank.  The fuel level is above the carb so fuel flows to the carb bowl.  Use a test tank (no pressure just gravity feed) to the carb----if runs ok, go back to the input of the tiny tank----same test.  You are just subbing the test tank for the fuel pump.  Also seen instances of where customers replumbed trying to get away from dry starts (setting for a time and fuel evaps).

BTW, this set up sucks.....fuel starve (as is sputter and die) then going UP HILL for extended time.  Tank is "lower" relative to the carb in "nose up" position and there is not enough gravity to fill the carb bowl completely in this high demand situation. 

Low pressure (carb) electric fuel pump is the fix.  Gas fills carb in a few seconds instead of cranking the guts out of starter to get the pump/mini-tank/carb bowl filled.  Golf carts love this fix.

 

[victor gramma]

On Massino 500 I don't have spark and power to fuel pump.

 Is there any fuse for ignition coil or pump?

 The wire diagram I found is probably for different model: https://www.manualslib.com/manual/1006793/Hisun-Hs500utv.html?page=390&fbclid=IwAR0tM_nxTmlImnCt26JKoMuQRGZpK-YfeQ26wKqjEMymTBdXgdVkgGHpPOM#manual

Victor Syracuse NY

Thanks.

 

 

[Ben1098]

The "power" for the ign and fuel pump is supplied by the ECU outputs.  ECU needs +12V @ BLACK connector P. 15 Ign=KEY ON and P. 18 VSS=ALWAYS HOT.  Check both as they are fused circuits.....18 always +12v and 15 is 0v KEY OFF and =12V KEY ON.

[Turkey 20k]

On 2/4/2021 at 8:26 AM, IslandHopper said:

If the engine is only cranking but not popping, backfiring etc. Then like T-Boss 410 said, the injector could be bad. Massimo does not have a inline  fuel filter, just a screen. This apparently leads to a lot of bad injectors. A common bad injector symptom is the motor will start and idle but fall off under acceleration.  In your case, there is nothing, so let’s look further.

Check the spark with a GOOD TESTER. I’ve been an equipment mechanic for 30+ years and I can’t tell you how many times I’ve seen a spark plug fire when laid on the engine block THEN NOT FIRE when it’s installed and under cylinder pressure.

Is the fuel fresh? In my shop it’s VERY common for flat fuel to cause a no start

If you truly have good spark and fresh fuel then  try this quick trick. 
Take the air filter off and shoot a little carb cleaner or starting fluid into the intake. Then crank the engine over....

1) Still nothing. You have a valve issue or a compression issue. (It’s not burning the fuel)

2) Motor starts  then dies. The Fuel Injector is most likely plugged or bad. (You’re not getting fuel into the cylinder)

I hope this helps.
 

How do you tell if valve is problem and how to fix?

[Alton]

My Tboss 550 will not crank. It will turn over and make a clicking noise, but won’t crank. What could the issue be ??

[Turkey 20k]

Does it sound like it's turning faster than normal?

If so it could be a broken timing chain or it jumped off the gear.  Mine did that.