Guide · 6 min
Why won't your equipment's gas engine start? Check it in 7 steps
Also called: plate compactor, rammer, pump or mixer won't start
By the SIMAQ technical team · Grupo ConstruMarket ·
Short answer
It's almost always something simple you can check without tools: engine switch ON, fuel valve open with fresh gasoline, oil at level (if your engine has an oil alert, a low level stops it from starting) and the choke in the right position. If that doesn't do it, check the air filter and spark plug. And if it still won't start, don't pull until the starter breaks: take it in for service. This applies to the Honda GX engines on SIMAQ plates, rollers, mixers and saws, the Honda GXR 120 on the rammer and the Loncin engines on the pumps.
checks, in order
need no tools
all are four-stroke
Which engine your SIMAQ machine runs
Every gas engine in the SIMAQ line is four-stroke: gasoline goes alone in the tank and oil goes separately in the crankcase. Find yours before you start checking, because that engine's manual is the one that rules.
| Machine | Engine |
|---|---|
| SQ60 PRO 2 rammer | Honda GXR 120 |
| SQ15 PRO plate · SQ36 PRO trowel · SQ28 PRO vibrator · SQREVG-365LTS mixer | Honda GX160 |
| SQ16 PRO saw · L34, L41 and L102 rollers · 2-bag mixer | Honda GX390 |
| L51 roller · L202 roller · double trowel | Honda GX630 / GX690 |
| 6 m truss screed | Honda GX270 |
| 1.2 m screed · SQMG28 backpack vibrator | Honda GX35 |
| SQWP30 PRO and SQWP40 PRO water pumps | Loncin G200F / G270F |
The in-order check (no tools first)
Run the check with the engine cold, on level ground and in this order. The first four steps solve most cases.
- Engine switch ON. It's the most common slip, especially when the machine changes hands.
- Fuel valve open and fresh gasoline. Gas that sat for weeks in a can or the tank loses its punch and gums up the carburetor.
- Oil at level. Many engines have an oil alert: with a low level, they cut the ignition to protect themselves.
- Choke closed for a cold start and open with the engine warm or already running.
- Air filter clean and seated. One clogged with dust floods the engine.
- Spark plug: pull it and look. Wet with gas means it flooded; black or crusted, clean or replace it.
- If it still won't start after all this, stop. Endless pulling breaks the rope or the starter.
If it flooded: it smells of gas and the plug is wet
It happens when you pull many times with the choke closed or with a warm engine. Open the choke, let the engine sit a few minutes so the excess evaporates, and try again with the throttle set as your manual says. If the plug is soaked, dry or replace it before the next try.
The rammer has one extra case: if it was laid down or carried tilted, oil can get into the air filter or the cylinder. Check the filter; if it's soaked in oil, replace it or take it in for service.
It starts but dies or misfires
- Dies when you open the choke: it's still cold; open it gradually.
- Dies under load or loses power: dirty air filter, or water or debris in the fuel.
- Only runs with the choke closed: dirty carburetor, typical of old gas. That's a shop job.
- Blue smoke or oil burning: take it in before the damage grows.
Store it right and it'll start next time
Most engines that «won't start» sat for weeks with old gas. Before storing a machine longer than usual, follow its manual for the fuel, close the valve, clean it and change the oil if it's due.
For hour-based maintenance (oil, filter and plug), use the Honda GX routine: first oil change around 20 hours, then every ~100 hours or 6 months. Several SIMAQ machines come with the Pro-Club maintenance kit so you start with what you need.
When to take it in for service
Take it in if the rope feels like it has no compression or is jammed, if there are metal noises, smoke or oil leaks, or if it only runs with the choke closed. If the machine is new, take it in instead of taking it apart. Order plugs, filters and parts with the machine's model at hand.
At ConstruMarket branches in El Salvador, Guatemala (CMARKET), Nicaragua and Panama. Request a quote from this guide and an advisor in your country will confirm the model and availability.
Common mistakes
- Pulling twenty times with the choke closed: you flood the engine.
- Using old gas from the storeroom can.
- Putting an oil-gas mix in a four-stroke engine.
- Topping up oil without finding out why it dropped: a leak is still there.
- Laying the rammer or plate down to move it: oil runs into the filter or cylinder.
Takeaway
Switch, fresh fuel, oil and choke: check those first, no tools needed. Then air filter and plug. If it still won't start, stop and take it in instead of breaking the starter. And store it the way the manual says: old gas is the most common cause.
Frequently asked
Why won't my plate compactor start?
Check in order: switch ON, fuel valve open, fresh gas, oil at level and choke closed when cold. If not, air filter and plug. The SQ15 PRO runs a Honda GX160.
Do SIMAQ engines take an oil-gas mix?
No. The Honda and Loncin engines in the SIMAQ line are four-stroke: plain gas in the tank and oil separately in the crankcase.
Why does the engine start and then die?
Most often: you opened the choke too fast while cold, the air filter is dirty, or there's water or debris in the fuel. If it only runs with the choke closed, the carburetor needs service.
How often should the engine oil be changed?
On Honda GX engines, the first change is around 20 hours, then every ~100 hours or 6 months, whichever comes first, and sooner in dust or at full load. For other engines, follow the manual.
Where do I get a plug, filter and parts for my SIMAQ machine?
At ConstruMarket branches in El Salvador, Guatemala (CMARKET), Nicaragua and Panama, or from the parts page. Have the machine model at hand.
