1990 351 Bogs at 2800 rpm

[hairlesshacker]

I have a 1990 TriStar 190 with the 351.

Recently it has started bogging down at WOT. Without a skier, it will only get up to about 3000rpm, and with a skier, it tops out at about 2800...
And when I turn a corner, the it drops down to about 2200, and sometimes won't do any more than that.. Usually it will gradually work back up to 2400-2600 if I keep it floored once I come out of the turn.

I am assuming it's a carb issue, and I've already got the rebuild kit from holley, just haven't gotten around to doing it yet.
(whenever I have spare time, I usually feel like skiing, not tinkering... then of course I get frustrated when it won't pull me right on slalom, and end up kneeboarding instead, since I don't need speed for that..)

Just wanted to ask here, is carb the most likely culprit? What else should I check? (I've checked fuel filters, but that's about it..)

[Kevin 89MC]

Definitely sounds like a carb issue, possibly the secondaries are not opening up. Rebuild is fairly straightforward, mine went well. I would suggest you change both the fuel filter (by the fuel pump) and the water separator (in the bilge). I chased a stumble after my carb rebuild, both filters looked clean, but new ones cleaned up the issue.
Good luck,
Kevin

[rjracin240]

Check your filter, fuel pressure, and fuel pickup in tank first before tearing into the carb. Definitely sounds like fuel flow limited.

[j.mccreight@hotmail.com]

Originally Posted by rjracin240

Check your filter, fuel pressure, and fuel pickup in tank first before tearing into the carb. Definitely sounds like fuel flow limited.

Did you get yours straightened out?

[hairlesshacker]

So over the winter I've rebuilt my carb...
And it didn't help. The engine still bogs down when pulling a skier...
And sometimes is tough to start. (sometimes starts right up..) But generally runs rough...

Here's what I've done....
rebuilt carb with holley renew kit.
replaced fuel water separator filter.
replaced fuel filter on the fuel pump.
checked fuel pickup in tank, it looks good.. checked anti-siphon valve, it looks ok..
removed and checked fuel lines between tank and filter, and filter and pump. They look good.

(changed oil, replaced spark plugs)

Changed distributor from points to EI from skidim.. Checked/adjusted timing after changing it out. (still running stock coil though)

I replaced the fuel pump, but haven't had a chance to try it out yet.. but when I had the old one off, I didn't see anything obviously wrong (it sucked when I pumped) - so I'm not optimistic that it will help anything..

I guess it's time to buy a compression guage? not sure what else to check at this point.
maybe it's just time to take it to a real mechanic...

[pkskier]

Replace the fuel lines the ethanol softens them up and the pump sucks and it collapses the line shutting down the fuel flow.

[hairlesshacker]

The hoses feel pretty firm, but it can't hurt to replace them... I'll give it a shot.

[lhkrueger]

Check your fuel tank vent. A restricted vent will reduce flow when there is demand, but allow a slow recovery when there is not producing an intermittant problem. Might be collapsed or kinked.

[thatsmrmastercraft]

Originally Posted by hairlesshacker

So over the winter I've rebuilt my carb...
And it didn't help. The engine still bogs down when pulling a skier...
And sometimes is tough to start. (sometimes starts right up..) But generally runs rough...

Here's what I've done....
rebuilt carb with holley renew kit.
replaced fuel water separator filter.
replaced fuel filter on the fuel pump.
checked fuel pickup in tank, it looks good.. checked anti-siphon valve, it looks ok..
removed and checked fuel lines between tank and filter, and filter and pump. They look good.

(changed oil, replaced spark plugs)

Changed distributor from points to EI from skidim.. Checked/adjusted timing after changing it out. (still running stock coil though)

I replaced the fuel pump, but haven't had a chance to try it out yet.. but when I had the old one off, I didn't see anything obviously wrong (it sucked when I pumped) - so I'm not optimistic that it will help anything..

I guess it's time to buy a compression guage? not sure what else to check at this point.
maybe it's just time to take it to a real mechanic...

A compression check would certainly be in order. Are you getting any backfires through the carb when the engine bogs down?

[hairlesshacker]

Yes, it did backfire once last time I had it out.