7.4LX 330HP MPI - The boat has close to 500hrs, owner seems very honest but you cant take anyone's word for it.. Says gimbal ring and bellows were done last year.. Boat has some stress cracks. Also says he kept having problems blowing impellers? One last thing he says every once in a while the boat will misfire and surge for a second then go back to normal. He says that it doesn't happen every time he takes the boat out, some days it does it some days it doesn't. Brought it to one shop they water tested and couldn't find anything wrong... Boat ran good that day.. Took it to another shop and they told him it needed a new ECM but who knows I feel like it could be many different things..(fuel issue, electrical, etc) I feel the boat is priced right - $15,000... I cannot water test everything is frozen but I can hook it up to the hose and check it out the best I can that way.. What should I do? Thanks.

Where is the boat located at? Fresh water? Salt water? It sounds like timing could be off, does it misfire through the carb or through the exhaust?

Get a GOOD Survey and have that engine checked out by a GOOD Merc mechanic. 15k sounds good until you find problems. Sunsation builds a great boat but one major area to check is the wood for all the seats and interior panels. In my boat almost all of the wood for the interior was bad, yes it is 8 years older but this aggressor could have the same problem as my Rocket did or the problem is starting. So survey, check engine, check interior. The impeller issue just might be the guy running in shallow water/beaching it and sucking up sand.

Where are the stress cracks?

Boat is up north near Canada too cold to really go through it right.. Fresh water its whole life.. It is fuel injected.. Owner told me some days its good some days it will misfire.. Sounds more electrical to me.. I'm going to check it out if compression is good on all 8 and starts up sounds good I think I'm going to pull the trigger.. My buddy works on boats isn't Merc certified but knows his stuff he told me he would give me a hand if needed.. Worst comes to worst put a few grand into it shes gotta be worth close to 20k. I just don't want a problem child if you know what I mean, I want to enjoy my summer not have to work on the damn thing every other week..

I didn't ask.. The guy was talking my ear off I forgot to ask a few things actually.. I'll get more info out of him soon...

Had a 98 aggressor, fun boat. Ran out of hull over 80 it was a chime walking ride. Stress cracks will be in the corner of the dash areas and if he really beat it on the top sides of the cockpit area. Engine hatch pad and seat wood rotted in my boat too.

Take your friend with you to look it over. Check everything. 15k is a good price but if it has bunch of small items/issues it can add up fast. Check the trailer tires, brake, lights can also add up fast.

I have a1999 Aggressor and it would misfire and surge some times. Check your fuel pressure when it is running rough, my problem was bad fuel pump.

I had that same engine in a previous boat. I had a problem with it cutting out and dying every once in a while. Turned out to be a clogged screen in the VST resevior. Other than that it was a great running engine. They only made it a couple of years.

Thanks guys I ended up buying the boat. I was wrong it actually has a 7.4L MPI which I figured was a little better than the LX in terms of newer technology.. I'm going to start diagnosing in the spring. I took a chance on it and just ran it off the hose. It fired right up sounded good, no way to test run in the middle of winter upstate..