Newbie - Bertram 28 Power question

[jgreen733]

Good evening all,

First time poster and new Bertram owner.
I recently purchase a 1987 Bertram 28 powered with twin 350 Mercruisers.
Motors have 1700 hours on them and have good compression in all cylinders. I have replaced all the plugs, caps, rotors etc.
I'm only getting 3600-3700 rpm WOT and topping out at about 18-20 knots.
My question is, is it worth replacing carburetors (they were pretty gunked up and have sprayed the crap out of them, as well as a ton of seafoam) and chasing my RPM issue or do i just bite the bullet and drop in 2 new motors. I would prefer not to spend $20g's but am afraid of spending $$$$ constantly chasing issues.
I get it, its a BOAT and I know that i will dump money into it anyway, but am just looking for some opinions.
Thanks in advance for your opinions and thoughts, and please take it easy on my as I know Whaler1777 and am constantly being told by him I know nothing.

[thuddddddd]

Have a mech do a full check with leak down to confirm they are worth keeping .. and then swap to EFI????? ... or buy those 170 yanys on a different thread (btw, someone was selling a couple of efi mercruisers with low hours for around 12k with gears.. they were doing a diesel conversion)

[thuddddddd]

BTW... my condolences for having to admit you know Maggs

[MarkD]

jgreene:

I run a 1988 B28 model and had the same motors prior to my repowering. You should be seeing 4400 or so and a more significant speed (Cruise at 3000-3200 would give me 20 knots with the old motors). Others may weigh in but I'd check the following first (if compressions are good, you should be making power):

- Bottom and running gear clean?
- Timing (important)
- prop configuration (sounds like it may be over propped)
- Fuel filters ?
- Perhaps check the throttle cables and make sure they are adjusted to open the linkage of the carb's all the way when in WOT

Good luck. Keep us posted.

Mark

[MarkD]

Where are you located?

[jgreen733]

Thanks for the quick responses, located in Island ParK, NY

[Tony Meola]

Do you still have the fiberglass fuel tank?

That could be the issue also if someone has put ethanol fuel in her. Otherwise check running gear, make sure everything is clean and make sure the props are correct.

[jgreen733]

Fiberglass tank was replaced several years back.

[mike ohlstein]

How dirty is the bottom? What size are the props? Clean fuel and air filters?

[Bruce]

Few things,
Make sure throttles at carb are opening all the way. Butterfly's should be in the verticle position both primary and secondary. Engines off of course.
Next is to make sure tachs and engines read the same, not uncommon at all to be off.
Third would be to check prop size with whats on there to what should be.
If all those check out then start chasing engine issues.

[jgreen733]

Thank you all for replies and advice.
Will keep you posted