2008 Tige 20V Marine power hesitation/loss of power

[JR200820V]

Hello all you genius Tige owners. Fairly new to the site. I am having an ongoing power issue that has me (and the shop stumped). Boat was backfiring last season and they messed with the timing likely when they didn't need to. Found out it was a missed impeller and she wasn't happy running hot. Now that is fixed and it is re-timed, it doesn't heat up much over 80 even on a hot day after a long run. As well, you can smell the fuel (more than usual) at idle and while surfing. Occasionally it throws alarms when coming back to idle from cruising and sometimes even at cruising. Hesitates on hard acceleration, but will eventually plane. With lots of weight in the boat, it won't plane at all, where as normally it would.

Done so far: Cap, rotor, plugs, impeller, fuel pressure test (by shop), timing (by shop)

I am at a bit of a loss, but it certainly smells like it is overfueling, running too cool, or missing spark somewhere

Help!

[JR200820V]

Did the ignition module as well

[freeheel4life]

Fuel pressure test in a shop is not a super accurate test. Have had fuel pumps test fine on a trailer but drop when you have a load on the prop.

[boatwakes]

Fuel pressure and compression test first, if all comes back okay do a cylinder drop out test. It sounds like you're down a cylinder.

[JR200820V]

Fuel pressure test in a shop is not a super accurate test. Have had fuel pumps test fine on a trailer but drop when you have a load on the prop.

Thanks! They claim the have fuel tested on the water and have said that it is quite stable under load, actually high if anything

[JR200820V]

Fuel pressure and compression test first, if all comes back okay do a cylinder drop out test. It sounds like you're down a cylinder.

Thanks! How do you do a cylinder drop test? Would this be the ECM making it drop? Thanks for the info

[freeheel4life]

Unplug each injector one at a time. Listen for RPMs to drop and then pick up when you plug back in the injector. If you have a hole that doesn't have any noticeable change in RPMs thats your offending cylinder.

[jslayde1]

... Now that is fixed and it is re-timed, it doesn't heat up much over 80 even on a hot day after a long run. ....

Is this fahrenheit or celsius? I'm guessing C since its about right for running temp.

If F, that is not very warm at all. Could be a thermostat stuck open...

[JR200820V]

Is this fahrenheit or celsius? I'm guessing C since its about right for running temp.

If F, that is not very warm at all. Could be a thermostat stuck open...

I believe it's Fahrenheit as it as the minimum on the gauge. I think they replaced the thermostat when they did the impeller (or so I was told), but having them check it again. An other ideas that would make it overcool? Thanks!

[jslayde1]

If its not warming up past 80*F, I would say more than likely the thermostat stuck open (or missing one). I guess next task would be to verify that the gauge is reading correctly and that in fact the engine is not warming up.

I'm not as seasoned as freeheel or boatwakes, but I would imagine the engine trying to run cold could cause some fueling issues...

[boatwakes]

JSlayde is correct, the fuel injection system doubles the fuel injector pulse width until the engine reaches 140* and then leans out to normal running parameters. It essentially is overfueling the engine until it reaches operating temp. What brand is your engine? Marine Power?

After performing the cylinder drop out test and determining if you're missing one or more, you will need to get an inline spark checker to determine if there's spark in those cylinders. We recently had what I initially thought would be two bad fuel injectors (because he had put the water hose in his fuel tank) on an 8.1 Mercruiser that turned into two bad spark plugs. So even if they're showing spark with the inline checker, swap in plugs to be sure.

[JR200820V]

JSlayde is correct, the fuel injection system doubles the fuel injector pulse width until the engine reaches 140* and then leans out to normal running parameters. It essentially is overfueling the engine until it reaches operating temp. What brand is your engine? Marine Power?

After performing the cylinder drop out test and determining if you're missing one or more, you will need to get an inline spark checker to determine if there's spark in those cylinders. We recently had what I initially thought would be two bad fuel injectors (because he had put the water hose in his fuel tank) on an 8.1 Mercruiser that turned into two bad spark plugs. So even if they're showing spark with the inline checker, swap in plugs to be sure.

It’s a marine power 5.7. If a bad thermostat was the case, then likely unrelated to the boat hesitating out of the hole, as it would not have yet reached operating temperature either way. Correct?