Dies at WOT

[tramsdell]

1987 110 v4 vro delete.

wot boat gets up and goes then after about 30 sec of wot operation the engine dies. Starts right back up without pumping primer . Happened with boat tank and aux tank. I suspect junk blocking the outboard mounted fuel filter and basically starving the engine?

 

[racerone]

Check for water in the fuel.-----Need to establish if it is fuel or spark related.-----So run with a timing light hooked up and observe the flashing light when engine cuts out.-----No money spent on this test.-----Will it keep running at 1/2 throttle , yes or no ?

 

[tramsdell]

1/2 throttle runs fine. Idle all day. And up through the rpms fine then just cuts out after leveling off at wot. fwiw, problem occurred before and after changing spark plugs(running apropriately gapped champion plugs) i guess it *could* be water in fuel, although problem persisted with a different tank and line setup. And my other boat ran fine on that tank. It may be saturday before i can get back on the water and I'll bring my timing light.

 

[racerone]

Could be a broken wire coming from the timer base, remember it flexes and moves..-----Timing light will help in the trouble shooting process.

 

[tramsdell]

This motor is new to me. Looks to have an oem style fuel filter on it, but according to internet pics... mine is upsside down. Seems to me that would do it, although i would think it would lose prime maybe?

 

[tramsdell]

Check for water in the fuel.-----Need to establish if it is fuel or spark related.-----So run with a timing light hooked up and observe the flashing light when engine cuts out.-----No money spent on this test.-----Will it keep running at 1/2 throttle , yes or no ?

Went out today now that i have a more apropriate prop. In the meantime i have changed the primer ball and hose from the boat to the motor, and took out the fuel filter that was clearly upside down, put one inline before the primer ball. Running better that time, longer between issues, It seems like WIF . Never had that in a boat, but it feels like the snow machines do when theres water in the gas. Stumbling around at various rpm randomly, and dying at wot. So i statred draining the tank through clear hose. Looks wet. Hopefully some fresh gas will straighten it up.

 

[tramsdell]

In trying to dial in, I'm starting to doubt my tach. For one thing the thing is SCREAMING along and the tach reads 3250. That and 18ft aluminum boat with 110hp on a 17p prop should be well above recomended rpm at wot, considering it was 15gal fuel, 2 relatively small adults, and 3 batteries. Maybe my tach is set to the wrong setting? What should it be on?

 

[Tim Frank]

This motor is new to me. Looks to have an oem style fuel filter on it, but according to internet pics... mine is upsside down. Seems to me that would do it, although i would think it would lose prime maybe?

Has it ever run properly for you?

If not, I would wonder about the fuel pump,.
Try and verify that it is the right one for that motor....specifically is it a sufficient output.
The PO's VRO conversion may have gone wrong.

 

[tramsdell]

Has it ever run properly for you?

If not, I would wonder about the fuel pump,.
Try and verify that it is the right one for that motor....specifically is it a sufficient output.
The PO's VRO conversion may have gone wrong.

no, never ran great for me. I did the vro bypass its still a vro pump. Just unplugged and blocked the oil hose. So output should be right. I hate to not "figure it out" but i only get out on saturdays and i can work on it all week, so im kinda just throwing maintenance items at it. Fresh gas will be in for the next outing along with freshly rebuilt carbs. Once the maintenance items are all complete ill feel more confident troubleshooting and either way these things ought to be done.

 

[tramsdell]

Quick update, put fresh gas in and 4 new spark plug wires(pretty sure they werent the problem but they were lookin crispy) took it out and ran like a dream. Thanks all!