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hi guys, I have a 1998 238 vista with a Volvo Penta V8 Small block with a Holly Carb, it came on the boat when I bought it.....my problem is I cant get the boat to plane off now.....was fine all summer until now......gets up to 2600 rpm and no more......according to GPS I am doing about 12-13 knots........that's all. typically I run around 3000 rpm @ 25 knots..........recently replaced fuel pump about 2 months ago but was running fine after that for a while......when at the dock I take it out of gear and can rev the engine up to 3500 or so.......any help would be great.........

thanks

First thing I'd look is check to see if you have any damage to the prop, then see if anything is blocking the fuel vent. If you wanna look a little more into it you can try replacing the anti syphon valve and the inline fuel filter going into the carburetor. Is there any backfiring when you try to accelerate? Could be the timing off or needs a rebuild on the carb.

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'99 258 Vista Cool Breeze II

No backfiring issues, the fuel pump was replaced a few months ago with the filter. Prop looks fine, some alage that I will brush off but everything seems to pointing at the carb..........

Yeah, I'd agree, but there are a lot of guys here who would know better than me. One more quick thing to check could be all your fuel line connections. I had a clamp come lose on my fuel line and the connection was a little loose and it was sucking in air as you went under a load and that was causing a lot of bogging down. I guess the only other thing I could think of before rebuilding the carb would be compression tests and checking the timing to making sure its advancing properly.

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'99 258 Vista Cool Breeze II

thanks for your help, I have a guy coming to check it out on Thursday, will let you know....

Thanks

You're welcome ... good luck and hope it isn't anything major.

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'99 258 Vista Cool Breeze II

Start with the ignition system, make sure the plugs are not worn/fouled and the gap is right, measure the resistance of the spark plug wires, check the cap n rotor. If you have an advance timing light you can check for full timing advance when you put the boat in the water (you can't do this on the water hose on land because you have to run the engine too fast for the water hose to keep up).
Then look at the fuel system, marine engines tend to have problems in the fuel delivery system:
fuel filter---> remove, dump out the gas into a large gas jar, let it sit and see what's there. Layer of water on the bottom? If so clean the gas tank
anti-siphon valve-->can be sticking and cause fuel starvation, my boat had this exact problem
vent--> can be clogged
Fuel pump you seem to have covered already.
Carb, may need a rebuild. I've had my Quadrajet done 2x in over 10 years or so.

My boat did this exact thing when I first had it and it was all because of the anti siphon valve and some debris in the carb.

Last thing, is this a trailer boat or did it stay in the water? Reason being if it had heavy marine growth on the hull it will really slow the boat down.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

Thanks LouC you have a lot of good information.....I have a guy coming this Thursday to loot at it.......I will keep you posted.....

thanks

My mechanic came to the boat last night, he checked each cylinder for compression each one put out around 185.....said it was good, pulled all spark plugs and all seem to be in great shape......he noticed some corrosion on the distributor cap connectors and the micro chip for the timing right near the distributor cap seemed to have some corrosion on it as well. he is replacing the dirstibutor cap and chip today. We went for a ride and he tried dumping more gas right into the barrels of the pump to see if that made any difference,,,,,,no difference....we will hopefully see today if the distributor cap and chip make any difference.......