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Re: 28 BERTRAM EXPRESS CONVERSION

Posted: Sat Jun 17, 2017 12:41 pm
by Fuzz
Dumb question but are you sure the engine is making its full rated HP?

Re: 28 BERTRAM EXPRESS CONVERSION

Posted: Sat Jun 17, 2017 12:55 pm
by DAYTRIP
I think you should verify your engine is running correctly Mike. In comparison to mine you have less gear in the water. I cruise at 33-35 at 4000 rpm which is probably less then 370 hp? You can find a hp curve for the Yamaha f250 and I will be happy to run at various rpm and tell you what I am getting.

My old one did what you describe to some extent but not super bad. I guess you are light. I think I am way light.

Let me know how I can help.

Jim

Re: 28 BERTRAM EXPRESS CONVERSION

Posted: Sun Jun 18, 2017 9:22 am
by topwater
Also what gear ratio is the transmission :?:

Re: 28 BERTRAM EXPRESS CONVERSION

Posted: Tue Jul 09, 2019 2:16 pm
by Mbiggerstaff
Well it’s been almost another year. I did not get to fish any last fall thru this spring because of Florence damage but finally got back on the water in May. I did add nitrous and propane to the engine and tried several sets of props. What I found is that the nitrous really helped with takeoff. A 2-3 second burst and the turbo kicked in and she was off. The props I finally settled on had me cursing at 23-24 kits at 75% power and 27-28 at full. The propane allowed me to decrease RPM by a few hundred for the same results. The problem that I continued to have is that my exhaust temp was running too high. 1100-1400 depending on load. I cleaned the inter cooler again and rechecked for exhaust blockage. Nothing helped. I was afraid I would burn a valve or have some major failure at those temps so I decided to go ahead and change out engines. I found a Yanmar 6ly3 RTO 480 hp. Same footprint as the old engine so I rented an boom forklift and swapped them out. It was surprisingly easy. The new engine is electronic so I’m having to get new controls to interface with the engine and the manual transmission. Glen denning is working on that and hopefully will have an answer this week. Will let you know how it turns out.

Re: 28 BERTRAM EXPRESS CONVERSION

Posted: Fri Jul 12, 2019 12:43 pm
by DAYTRIP
That’s a big change mike. Isn’t your current engine a 315?

Re: 28 BERTRAM EXPRESS CONVERSION

Posted: Sun Jul 14, 2019 9:50 pm
by Fuzz
I am really surprised you did not melt that engine down. 1200f is getting pretty hot for a natural, I would have thought a turbo engine would have melted at that temp.

Re: 28 BERTRAM EXPRESS CONVERSION

Posted: Mon Jul 15, 2019 5:58 am
by Mbiggerstaff
The current engine is a 370

Re: 28 BERTRAM EXPRESS CONVERSION

Posted: Mon Jul 15, 2019 6:18 pm
by fallguy1000
Hard for me to believe you can't get her to 30.

Re: 28 BERTRAM EXPRESS CONVERSION

Posted: Mon Jan 20, 2020 6:05 am
by Mbiggerstaff
Well its been quiet an adventure getting the new engine running. first problem was that the engine is all electronic and my outdrive is mechanical. I spent several months and went thru several different systems trying to only use one control to both shift and throttle. The companies systems that I tried assured me that theirs would work but after much wasted time and money I finally discovered that Yanmar has its own computer language so you have to buy their control. Their control does not have an actuator that will shift a mechanical transmission so I had to go with 2 controls, one for throttle and one for shift. No big deal but a lot of wasted time. Finally got it running and went for a test drive and the engine would not spool up under load and was loosing oil out the exhaust. That was an "OH SHIT" moment since the engine was sold to me as a 500 hr RTO. Pulled the engine and shipped it off to georgia for diagnostics. They found a blown piston on a 3000 hour engine. Ebay seller was noncooperative with refund/return so I had to pay out of pocket for a complete rebuild. Several months later the engine makes it back to me. Got it reinstalled and went for a maiden run yesterday

I HAVE A NEW BOAT!!! The extra 100 hp made the boat run like I had hoped it would from the beginning. It leaps out of the hole like a rocket. Cruises at 26-27 KTS at 70% throttle burning 9-10 gph, 5psi boost, and 40% load. WOT 32KTS. Trolling speed .7gph. She stays on plane at 13kts which is great for me as I do love some high speed whoo fishing.

Now I can get back to work on my outboard boat. Its getting close. Just the fairing and sanding and fairing and sanding and ...... left to go

Re: 28 BERTRAM EXPRESS CONVERSION

Posted: Tue Jan 21, 2020 10:47 am
by fallguy1000
Glendinning Smart Actuator2 did not work?

I am buying 2 of them!