72 1150 dies at wot

[Chief847]

Hello I have a 1972 1150 tower of power. It runs fine on the muffs and I was finally able to get to the lake today. I wasn't able to take it out as the lakes around here are either closed or just to high to launch by yourself. I back the boat far enough to start in the the lake and it ran at idle just fine while setting on the trailer. Kick in gear and seemed to run fine (no misses or apparent hesitation). As I slowly moved the throttle forward while in gear everything seemed fine to what I believe was around 3/4 throttle. I back it off and tried again still fine and tried to blip the throttle to WOT or really close to it. When doing so the engine died. Seemed to lose power and shut down. Placed in N and fired right back up again same thing and it died. Again fired right back up. I tried this several times always same result. The boat seemed to be pushing a good amount of water with the prop but didn't seem to be pushing very hard against the trailer though either!

I tried running the motor and half throttle or so and slowly move toward WOT and it died.

I've had the fuel pumps off they seemed fine and I replace the fuel lines under the hood as they were very brittle and falling apart.

What I'm I missing or where should I start.

Thanks Emil

 

[jimmbo]

Sticking Floats, dirt/gum/varnish in the carbs/hoses/fuel pickup/fuel filter

 

[Chris1956]

Try pumping the fuel primer bulb. If that fixes it, the issue could be fuel filters or other restriction. If primer bulb collapses, likely an antisiphon valve issue.

 

[Chief847]

I kinda figured something in the carbs. I really don't wanna pull them then have to do a link and sync lol. I know the fuel hose from the tank to the engine is only a couple of years old and when not in use I keep it in the garage. The primer bulb stayed pretty firm while it was running in the lake.

I've seen/read that pressure from the lake that causes the issues to show themselves compared to the muffs is that true?

Would this be why the engine run fine at idle and even revved up on the muffs but not want to stay running when revved up in the lake?

 

[jimmbo]

99% of the time. the Link and sync is just a check/verification

It takes very little power and thus fuel to rev an engine on the muffs. No Back Pressure, no Load, the engine can rev past 5000 running on only 3 cylinders when on the muff.

 

[Chief847]

Well that's good to know!!! not comforting but good to know lol. I"m guessing ill try cleaning them out and check the filters that set on top of the carbs. I had the top one off when I was changing the fuel lines and it looked good so I was hoping they all would have been.

From what I was told it was rebuilt about 10 years ago used about 10 hours then set for the last 10 years.

 

[MatthewtheDruid]

Check all fuel lines, connections, primer etc, i has the same issue with my 77. Could be sucking air, clogged or closed tank vent, stuck check valve, antisiphon valve, fuel pump. Rotten fuel pickup, start with the tank and work toward engine, no detail too small

 

[racerone]

They just " sound " fine on a hose !-----They bark and roar running on 4 or 5 of 6 cylinders.----Orderly trouble shooting can / should be done.

 

[Texasmark]

If your fuel lines have started to dissolve, rendering tiny black particles, you could have some of them in your carbs. I had such and I found my problem to be a tiny speck of black hose intermittently blocking my high speed jet in one of the carbs. I didn't find it till, after thorough cleaning of the carbs, 100# air pressure blowing out of every hole I could find in the casting dislodged it.

Another thing I experienced with my "tower" was that I'd run the engine out of fuel if I ran at WOT trimmed out for any length of time. Rerouting my fuel line from the tank to the engine solved that problem.