Engine surging

"We have a 1989 3.0 with 130 h

"We have a 1989 3.0 with 130 hours on it. This boat has not been used in 2 years. The other day the Engine started to surge at low to medium speed, the rpm was surging about 200 to 300 rpm. Can any one in the water world give me some idea what to look for?"

"Was the engine surging, or ju

"Was the engine surging, or just the tachometer?
If it was the tach,clean up and tighten your electrical connections especially at the coil.

If engine is surging, start with your fuel filter/s, and fuel lines right back to the tank.

Please let us know your progress."

Also check for restriction in

Also check for restriction in tank vent hose. Restriction will cause fuel pump to create vacuum in tank that pump cannot overcome.

Bob

Lets keep this simple for now

Lets keep this simple for now and treat the fuel tank with dry gas. A boat with that little hours on it would no doubt have water.

"I was thinking of the problem

"I was thinking of the problems we have here in the south with "dirt daubers", mud wasps, plugging every available hole with their nests. Harry did say it had set for 2 years.

Bob"

"Hey thanks for all the replys

"Hey thanks for all the replys. last night I took the filter out of the fuel pump and it was crusty in the bottom of the bowl, I then took the screen filter out of the carb and that also had gunk in it. Yes the boat sat for two years with a full tank, I added a octane booster before we went out on the lake and it seem to run ok, the problem came when I added fresh gas. Yes the engine was surging not the tach. We live in VA. and yes I had to dig out all mud dauber crud out of alot of holes. Should I drain the tank or get a water fuel seperator. I am a little nervous about replacing the filters and going out on the lake to see if that worked. Can I use a can of heat to take out the water, we used to do that on snowmobiles in the winter. Any Ideas out there?"

"after 2 years, I would recomm

"after 2 years, I would recommend disposing of the fuel. run your lawn mower on it.or start campfires. parts cleaner? water seperator always a good idea."

Va has made the change to 10%

Va has made the change to 10% ethanol. Dry gas uses alchohol to absorb the water and alow you to burn it. The new gas will do that on its own. The trouble is that when the water mixes with the ethalol it dramatically reduces the octane of the fuel. Since I have not yet met a boat tank without some water try adding octane booster see if it changes.

"Hey I have to thank all of yo

"Hey I have to thank all of you so much for the information. I did change out both filters and took it out this weekend and it seemed to run pretty good I think. I did purchas a fuel water seperator and I am going to put the thing on this week. The boat is a 1989 dynasty regency. I have anouther question. I have a top end of 38 mph at about 5,000 rpm. Dose this sound about right? Sorry for all the questions but this is the first boat I have owened and I don't have any manuals with it. Thanks to all again!!!"

"No reference material at hand

"No reference material at hand, but I think 3.0 is supposed to run 4,200-4,500 rpm wot. 5k sounds a little high. Never personally run any marine eng wot for very long. find it's "sweet spot" where mpg and mph seem best.

Bob"

Find out what your max r.p.m.

Find out what your max r.p.m. should be and change your prop accordingly. Sounds to me like you probably need a little steeper pitch.