frydaddy

My 70 will run normal then drop down to around 3k rpm's and won't power up again. Had it checked and the shop I took it to said the power pack and all checked ok, said I had a clogged carb. We'll it did the same thing, back to the shop and the same story, nothing showing wrong.

They said they ran it in the 'pit' full throttle for 1/2 hour and it ran perfect. If it does it again, I can pay for a mechanic to ride on the boat and try to diagnose it on the water. I didn't take it to the dealer (mistake) but I thought a shop could diagnose all problems at the shop. Not much fun having to putter all the way back to Navy Point. It's been getting me about a mile out in the gulf before doing this both times.

Is there problems that only show themselves when you are on the water with real running conditions, or have I really been taken?

fishnfever

Could be a cracked or bad connection with the fuel line.

DOUBLE "D" & LV

Sometimes the problem can only be duplicated in real conditions. Does this happen in the same amount of time each time, and does it happen all the time? How long does the engine run when it happens? Does the engine have to be run over a certain rpm before it will act up? Do you have the same fuel supply amount when this starts? Even though your powerpack checks out, they can be intermittent when they act up until they crapout completely. If you were to turn the engine off and restart it, will it still not run correctly? Have you tried pumping the primer bulb and using the choke to see if it makes a difference? Does your alarm work or do you have a warning gauge?- I ask in case the engine is overheating and you do not hear it telling you.

orca3

Try running it with an external tank,if runs ok the tank vent is clogged, also a bad stator can cause the same problem.

splitshot

after two trips to the shop (if they charged you normal rates) and didnt fix the problem, why would you have to pay for them to ride and fix, if they didnt fix it the first two times ?? seems to me if the problemis still there they should ride with you and fix for free, because they didnt fix it the first two times....maybe i'm wrong ??

frydaddy

They didn't charge the second time but I'm still chapped from the first since it isn't fixed yet.

I changed out the fuel pump before I did anything, the diaphram in it was shot after 25 years of use.

Have pumped the primer bulb when this happens, it doesn't change it. It has happened the last4 times I have had the boat out, I can't even get out to catch my 2 snapper yet. I run it at 5,000 rpm to go out, it drops to 3,000 about the time I get to Pickens or at the pass, that's from Navy Point.

It keeps doing it when I turn it off and re-start. The last trip out I turned it off by the base and fished some schools of spanish for about 30 minutes, cranked up and it ran normal back to Navy Point. I start with a full tank every trip, 18 gal and the vent line is clear, it overflows when I top it off.

I'll try new gas line and bulb tomorrow for Sat. trip even though I don't see any cracks or leaks, new lines were put on this season in March. Put in a new set of plugs today, even though they were new in March also. The shop pumped out a gallon of gas cheking for water, as well as myself, looks good and clear. Have added the new additive for the ethanol gas so I don't feel there's a problem from that.

I couldn't beleve ths shop couldn't diagnosis everything and didn't beleive the guy's story about some diagnosis having to take place in actual conditions. At least I don't feel like I've been took. Hate to buy a new power pack without knowing for sure but may have to try that next. Just replacedit 3 years ago.

DOUBLE "D" & LV

Your trigger/timer base could be going out also. I have had 4 in the last 2 months on 2 brands of motors that would be intermittent on some and only at higher rpm's on others.

lastcast

DOUBLE "D", whats a trigger/timer base? Never heard of it before. Thanks.

Skip

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dumbass

have you cleaned out the internal fuel filter? my engine does the same thing sometimes. either when i run at really high rpms for an extended time or when i run in a solid chop that keeps the boat bouncing around. i have yet to diagnose it. therory A could be that the chop is stirring up particulates in the fuel(10yr old fuel tank) and cloggin up the internal fuel filter. every time i check that thing it has little rusty looking pieces in it. theory B couldbe that bigger pieces are blocking the fuel lines somewhere. i just replaced the in line FF/WS with a clear bowl type so I know its not water in the tank. if the motor bogs down at 3k rpm, like yours, the only fix i have found is to let it sit for awhile or to release unscrew the water drain at the bottom of the bowl for the FF/WS. by doing that it seems to release some pressure in the fuel lines and for some reason it works afterward. this doesnt make any sense to me and i'm fairly mechanically inclined. the only answer i can come up with is particulates in the fuel line are preventing enough flow to get the motor over 3k rpms. i have a 90hp yamaha oil injected 2 stroke. if any of my problems sound like yours, you can try my solutions. i have no problem at lower rpms and my motor has done this off/on for 3 years. she always gets me home and this problem usually only happens when i have my bay boat in seas to choppy to be comfortable in anyway.

frydaddy

I've never heard of a trigger/timer base, does it have something to with advacing the timing like on a car?

I did get the shop to switch the power pack out with one he had from another motor so I'll see if any of the stuff I've done will make a difference tomorrow.

Havent's found any trash in the in-line filter and the tank is an aluminum I had built just three years ago. Blew into the vent and it went in and then came out with a strong gas smell. No signs of wasp or anything else and when filling up, gas gushes out with a good stream.

Thanks for all the help, will see what happens tomorrow.