Replacement engine from Rapidomarine...

[wca_tim]

Re: Replacement engine from Rapidomarine...

did the original engine ever run well in the configuration you got it in? Or did you buy it and it wouldn't run well?

If you never had the original engine running well, the question might be what was swapped over from the old to the new?

How about the rocker arms? Are you certain that they are the correct ratio and for the correct engine? If you didn't put the top end of the previous engine together, never know what some one else (idiot) might have done...

In addition, have you everr run the boat with a good running engine and the prop and drive combination that's on it?

What are the drive gear ratio, boat size (ie weight and length approximate), and what kind of a prop is on it. It would act like this if it were way over propped, or if someone put a different gear ratio drive on it...

Just thoughts...

 

[John_S]

Re: Replacement engine from Rapidomarine...

Only because another thread has found wrong plugs, what are the iridium plugs you are running?

 

[redjmp]

Re: Replacement engine from Rapidomarine...

Send the motor back. Refer Raul to this thread and tell him the guys at iBoats have exhausted all other ideas.

The problem lies within the block and heads.
Having the wrong cam alone will not give those kind of compression #s.
It would have the opposite effect imho.

210 is too high.
Based on that alone I would insist on having one shipped that runs 87 octane like it should.

Just be done with it and get a replacement.

Chalk it up to a rapido screw up somewhere.

Its rare but does happen from time to time.

 

[cpt ron jc]

Re: Replacement engine from Rapidomarine...

as i read through all this....i just bought a 4.3 long from rapido,i pray i dont have these issues,i wont know until dec sometime,im in the process of buying all new parts to fit on this block,and its going to cost,makes me wonder,should have bought a complete drop in,well im still going to be below cost of complet engine,i pulled engine im going to let a shop handle most of the install it will be worth it let them deal with ,they have all the resourcess i dont plus it wi;; be freezing by then i would send that engine back to raual,tell him y want another one,good luck kevo

 

[choochooharley]

Re: Replacement engine from Rapidomarine...

I agree the compression is too high I rebuilt a bike one time and had the cylenders bored out .20 or .30 over i cant remember but anyhow the compression was so high that with the motor cold the starter would barely turn the motor over and once it warmed up forget it the starter wouldnt even think of turning it over and it wouldnt even start by kicking it. The bike acutally lost performance with new pistons and head work. I think it was because of such high compression.

 

[swampy2646]

Re: Replacement engine from Rapidomarine...

i haven't read every post but is it at all possible that your outdrive was replaced with a different one with the wrong ratio?? this happend to a friend one year , the marina replaced the drive with the wrong one in the beginning of the season and he wasn"t turning more than 2800 rpm. it wasn't till we pulled the boat that we realized the problem.

 

[kewlkatdady]

Re: Replacement engine from Rapidomarine...

Me too...
My build starts this weekend.

as i read through all this....i just bought a 4.3 long from rapido,i pray i dont have these issues,i wont know until dec sometime,im in the process of buying all new parts to fit on this block,and its going to cost,makes me wonder,should have bought a complete drop in,well im still going to be below cost of complet engine,i pulled engine im going to let a shop handle most of the install it will be worth it let them deal with ,they have all the resourcess i dont plus it wi;; be freezing by then i would send that engine back to raual,tell him y want another one,good luck kevo

 

[Kevoz]

Re: Replacement engine from Rapidomarine...

did the original engine ever run well in the configuration you got it in? Or did you buy it and it wouldn't run well?

If you never had the original engine running well, the question might be what was swapped over from the old to the new?

How about the rocker arms? Are you certain that they are the correct ratio and for the correct engine? If you didn't put the top end of the previous engine together, never know what some one else (idiot) might have done...

In addition, have you everr run the boat with a good running engine and the prop and drive combination that's on it?

What are the drive gear ratio, boat size (ie weight and length approximate), and what kind of a prop is on it. It would act like this if it were way over propped, or if someone put a different gear ratio drive on it...

Just thoughts...

Everything is the same equipment removed from the good running but bad block boat, simply removed and replaced...Engine would bring boat to plane easily with very same equipment I am using now.....I am in the process of gathering tools to find cam timing of new versus old cam, have to find a degree wheel with pass through center so I can turn engine, my degree wheel will not work with this engine, looking for my drag racing buds for this..I will not deal with replacing this engine without knowing I cannot make it work, I am just not physically or mentally to do that all again just yet...but, I am going to forward this thread to Raul just so he is aware of what we have all tried...I will get another compression up here with both gauges as soon as I have stripped the exhaust manifolds off again...
thanks again for all your help,
Kevo

 

[fat fanny]

Re: Replacement engine from Rapidomarine...

Kevos have you even personally spoke with Raul? It seems to me that his company is mentioned allot here and I have heard of some good reviews on his products with that being said I would think that the press he is recieving off this thread would raise his eyebrow a bit to the lack of future buisness. I think that before you crack open the internals of that engine you should @ least speak with him especially for the amount of money you paid and these days I don't care who you are every penny counts. Without going into to much detail you should of had a turn key deal not counting your add on's so why mess with something that you already paid for to be right to begin with.

 

[cpt ron jc]

Re: Replacement engine from Rapidomarine...

Me too...
My build starts this weekend.

good luck let me know how it goes,in my case my old engine has rust every where so im buying all new parts,intake manifold,exhaust,risers,fuel pump,cir water pump im even buying a new 4 barrel carb from summit,right down to new starter,valve covers,if it looks rusty i will replace it i figure its best to replace to avoid problems once this engine is in,i hope we have good luck with the block ,y know theres a lot of adjusting to do when you go this route ,good luck.

 

[Kevoz]

Re: Replacement engine from Rapidomarine...

Yes, I have spoken with Raul, he offered little help..........

Can anyone help me with cam timing specs of the original marine cam in this engine, finding a spec sheet online? I cannot seem to find anything that I need, I need timing specs not just lift specs which I found in the manual...
cheers,
Kevo

 

[coheej]

Re: Replacement engine from Rapidomarine...

Yes, I have spoken with Raul, he offered little help..........

Can anyone help me with cam timing specs of the original marine cam in this engine, finding a spec sheet online? I cannot seem to find anything that I need, I need timing specs not just lift specs which I found in the manual...
cheers,
Kevo

Kevo, I also could not find the cam timing specs in the Mercruiser manual.
I found what is supposed to be a stock replacement cam from an aftermarket company. I'm assuming your motor has a hydraulic flat tappet cam and not a roller cam.
The specs for the aftermarket cam are as follows:

Lobe lift on both intake and exhaust is .273"
Valve lift on both intake and exhaust is .410"

Cam timing at .050" lift is:
Intake: opens 10 ATC closes 33 ABC Duration 203
Exhaust: opens 41 BBC closes 7 BTC Duration 214

Intake Center Line is 111

 

[Kevoz]

Re: Replacement engine from Rapidomarine...

Kevo, I also could not find the cam timing specs in the Mercruiser manual.
I found what is supposed to be a stock replacement cam from an aftermarket company. I'm assuming your motor has a hydraulic flat tappet cam and not a roller cam.
The specs for the aftermarket cam are as follows:

Lobe lift on both intake and exhaust is .273"
Valve lift on both intake and exhaust is .410"

Cam timing at .050" lift is:
Intake: opens 10 ATC closes 33 ABC Duration 203
Exhaust: opens 41 BBC closes 7 BTC Duration 214

Intake Center Line is 111

Thanks heaps, that's at least somewhere to start....
cheers,
Kevo

 

[John_S]

Re: Replacement engine from Rapidomarine...

This might provide some specs:http://www.gmpartsdirect.com/performance_parts/store/catalog/Category.jhtmlCATID=304.html

I only found lift in the Mercruiser manual, and wasn't sure of what your original motor was or replacement, flat or roller, balance shaft yes/no, etc..

 

[Evinrude Boater]

Re: Replacement engine from Rapidomarine...

Yes, I have spoken with Raul, he offered little help..........

Well that helps me make up my mind. Customer service starts after the cash register closes. I think I'll try my luck at Crosstown Engines in Toronto.
I wish I could offer you some suggestions Kevoz but fact is, you're far past my knowledge.

And with that, I jump rank.

 

[Bondo]

Re: Replacement engine from Rapidomarine...

and I will check for exhaust restrictions which I dont think I have but, hey, I am human, I could have dropped a box of cigars down one of the exhausts, who knows, lol.

Ayuh,... Are the shutters where they belong,..??

I've seen 'em get burnt up, 'n fall into the lower y-pipe or farther...

 

[Lou C]

Re: Replacement engine from Rapidomarine...

Your compression test readings are high but I don't think that has anything to do with the low rpm you are getting at full throttle. The 14 inches of mercury at is low though..

My stock non-vortec 4.3 compression pressures vary from 165-185

One thing not discussed, is the boat propped correctly, does the outdrive have the correct final drive ratio?

My boat had a problem with the anti siphon valve, it was restricting fuel flow and the engine could not even plane out the boat...

Also it came with the wrong prop, it had a 14 1/2 x 19 which was correct for a V-8 Cobra on this boat, but the V-6 Cobras were supposed to have a 15 x 17 and when I put that one on my WOT rpm went from 4200 to 4600 which is in spec for a 4.3 4bbl Cobra V-6...

 

[skippyon1o1]

Re: Replacement engine from Rapidomarine...

Ayuh,... The oil can't go beyond the cam, til the motor runs...
It's pumped up to the heads by the lifters, through the pushrods...

You Know that's what I was thinking ,while recently installing the rocker arms I bent one pushrod ,and grabbing the first one I found I noticed no hole through it ,should I be looking to see if oil is coming up? It seems I remember that solid lifters are different but I don't remember ,I have 2 aq170s'

 

[coheej]

Re: Replacement engine from Rapidomarine...

You Know that's what I was thinking ,while recently installing the rocker arms I bent one pushrod ,and grabbing the first one I found I noticed no hole through it ,should I be looking to see if oil is coming up? It seems I remember that solid lifters are different but I don't remember ,I have 2 aq170s'

You may want to start another thread, but hopefully you didn't use the pushrod that didn't have a hole. Even with solid lifters you still need pushrods with holes to deliver the oil to the top of the head. In most engines you will still get some oil up the pushrods when priming, although that is not the purpose of priming an oil pump. Priming until the oil pump produces pressure on the guage is all that needed.

 

[Bondo]

Re: Replacement engine from Rapidomarine...

Originally Posted by Bond-o
Ayuh,... The oil can't go beyond the cam, til the motor runs...
It's pumped up to the heads by the lifters, through the pushrods...

You Know that's what I was thinking ,while recently installing the rocker arms I bent one pushrod ,and grabbing the first one I found I noticed no hole through it ,should I be looking to see if oil is coming up? It seems I remember that solid lifters are different but I don't remember ,I have 2 aq170s'

Ayuh,.... That quote is from pages ago,...

Like coheej says,... Start your Own thread,...

Kevoz has enough Problems here, the confusion of your Hi-jack ain't helpin'....

I just stole this from Don to point ya on your way,....