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Matthew John
Matthew John, Marine Mechanic
Category: Boat
Satisfied Customers: 30
Experience:  Marine Technician, Certified in MERCRUISER AND MERCURY OUTBOARDS (Current), EVINRUDE, SUZUKI, YAMAHA, HONDA.
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I have a suzuki dt 150 efi that wont rev past 3660 rpm. If I

Customer Question

i have a suzuki dt 150 efi that wont rev past 3660 rpm. If I push the throttle any farther it dies.
JA: Sometimes things that you think will be really complicated end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so the Marine Mechanic can help you best.
Customer: Motor revs fine in reverse, but not in forward gear. Seams to have fuel, primer bulb is hard. Compression is all 125 cranking cold. New plugs, all cylinders have spark
JA: Is there anything else important you think the Marine Mechanic should know?
Customer: no
Submitted: 2 months ago.
Category: Boat
Expert:  Matthew John replied 2 months ago.

Hi my name is***** to Just Answer ! I will be assisting you.

Expert:  Matthew John replied 2 months ago.

Just wondering a couple of things to get started; Do you know the Engine Hours and service history?

How did the fuel look and All the fuel filters?

Are you able to connect to a portable fuel tank and go for a run to isolate a possible problem with the boats fuel supply?

Also, are you able to tie the boat to the dock, put it in forward gear and perform a cylinder drop test? Alternately disconnect each Fuel Injector and listen for RPM drop and bump back up again when reconnected. If there is no RPM change while performing this test, it means that cylinder is working improperly and we can take it from there.

I would normally have the injectors cleaned every 500 to 750 hours of operation, depending on fuel quality.

Regards,

Matt

Expert:  Matthew John replied 2 months ago.

If possible... It would be ideal to check the fuel pressure at the High Pressure Rail. There will be a schrader valve to connect the gauge to.

Expert:  Matthew John replied 2 months ago.

Actually, for your model engine, you would have to install the fuel pressure gauge In Line on High Pressure Line.

Fuel pressure should be 36 PSI

Expert:  Matthew John replied 2 months ago.

Hi there,

Just a quick follow up call to see how you went...

Please don't hesitate to let me know of any concerns you may have in the future!

Be sure to hit my Star Rating ! ! ! ! !

All the best!!!

Matt

Customer: replied 2 months ago.
I have already isolated the fuel supply that didn't affect it. Fuel filter are all changed and good. I haven't been able to t into fuel supply yet. Every plug I have pulled off you can hear the difference in load. I already tried that when I did compression to make sure they were all hitting.